Going by a glance at your photos only:

I'd take out the wall and just have the natural contour. If the slope is too abrupt make it more gentle. The waterfall is OK but needs some planting behind to obscure its origins and screen out the distracting view beyond. I would also take out the patio(?) off to the side of the stream.

Otherwise you have a good setting for some nice flowing mixed borders and a sweeping lawn. Use glyphosate to beat back the weeds. If there is not time, money or inclination for featuring large groupings of herbaceous plants (annuals, bulbs and perennials) use shrubs and trees throughout the beds (instead of in combination with herbaceous plants). Choose kinds tall and bushy enough to cover the (mulched) soil and suppress future weed growth (some trees and blackberries etc. will always insinuate themselves and have to be extracted).

Hello. Tree swings, baseball equipment, and 4 children will overrule 'impressive' most of the time. Maybe put that objective off for the future when the kids are older. ; )

Your photos do not disclose any information about how your home relates to the yard. Maybe walk to the dreaded chain link fence at the far perimeter and take a photo looking toward the house so posters can give you more ideas.

The "hideous chain link fence back drop" makes you cringe because there is no interesting foreground to divert your attention. Fortunately you have the secure retaining wall to work with, a terrific asset. A trio of shrubs (high, low, and medium) with good all-season structure and distinct colors or textures along with some self-seeding annuals and perennials planted behind the wall will set it off nicely. (They will get trampled, so make sure they are not too delicate.) Add in your chosen smallish trees several feet on a diagonal from each end of the wall, and you're good to go for now. Leave the rest open for rambuctious play.

Experiment with your roses in the sunny spots along the sides and your hydrangeas in the less sunny spots. Thus when the kids are older (faster than you can possibly imagine) you will know exactly what you like and where you will put them.

Bboy, thank you for you comments! I agree, the "patio" is atrocious and we'll get rid of it as soon as we can put in something more suitable. I really like the idea of large groupings of plants as well.

Catkim, you're speaking my language.
"Hello. Tree swings, baseball equipment, and 4 children will overrule 'impressive' most of the time. Maybe put that objective off for the future when the kids are older. ; )"
I have high aspirations. :D
I'm an avid rose lover, I had to leave all but one of my plants behind as I moved. It came to taking the pond, or the roses. Roses are cheaper to replace. I like the idea a lot of using them with hydrangeas in the sun/shady areas.
And I'm glad you like the wall, I like it a lot too! The reason I put it in was to break up the "line" of that back slope. It's too big to work with singularly (fifty feet, easily), and framing it will make it a nice focal point that can hold it's own next to the pond - which I intend to have heavily planted at some point.
I'm having a hard time visualizing you you mean here:
Add in your chosen smallish trees several feet on a diagonal from each end of the wall... Can you elaborate?
I didn't mention in my initial post - which was already too long - I intended to break up the back area with 3 indivual areas: The pond, the raised shady bed, and something else in the back right corner, I'm still clueless what to put there. I am also planning a second patio area with seating back by the pond, and I also intend on a walkway coming off of the side of the patio (near the garden) to curve around the side of the yard and lead to the pond, leaving the yard open, so the kids have plenty of grass to beat down.
Here are more pics of the rest of the yard and the house.

Taken from the top of the back slope:
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From the back patio, you can see the telephone and electric lines I have to be careful of (why I have to plant short trees. And my mini-me with her garden spade. :)
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Destany~It sounds like we have similar situations in our yards: the need for an open, grassy middle, with the sides being the spaces for flower or shrub borders, backed by less than lovely fences, and criss-crossed with power lines. So I understand your situation very well!

But, you have a few more challenges, and bigger issues to address first, ie the slope and the property easement issue. The retaining wall you've built tends to stop the eye, and doesn't relate to your pond and its rocks. If you buried some big boulders into the sides of the slope instead, it would look more natural, and the pond could be even more lovely if you used larger boulders around it as well. It looks a little plunked down right now. Here's a picture of a small waterfall that I found in cyberspace, to illustrate my point.

As you can see in the photo, the plant material at the top of the falls obscures the fence, and whatever is planted alongside it. This could be an effective way to incorporate the pond and retain the slope. The actual plant materials used would, of course, vary. What do you think? :)

Here is a link that might be useful: Small Waterfall with Rocky Slope

Wow, that is lovely! I really do love your idea about putting some boulders on each end of the retaining wall to incorporate it. Very nice!
And I'm in 100% agreement about planting the upper area of the waterfall to obscure the source as well as using some larger stones. They're are some there, but they're covered over by grass and weeds at the moment. Gosh, this area is so naked, despite the grass. What a pretty picture you found, that is very similar to what I'm going for and I do like the natural feeling to it!

I'm starting to think about some small evergreen overhanging shrub type things to plant next to the pond. Junipers would be very very nice, I think, to sort of grow over the sides and break up the solid stone setting - as well as provide a bit of height. Coupled with some large things planted behind and at the top of the waterfall, could add a bit of mystery that's much needed. I also like the idea of growing things on the rocks. The whole thing is just too bare.
Thanks so much for your suggestions, I'm getting some pleasing mental images!

Boulders, good idea.

Let's see if I can do a visual with the keyboard:

wall:.......................====================
boulders: OOOO..................................................OO
................OOO.......................................................O
trees:.......... Y..............................................................Y

Not so precisely symmetrical (especially the boulders!), and not stuck smack on the ends of the wall, nor too close to the wall. No idea if that will really work, and no idea what kind of trees. Maybe you only need a tree on the left; play with the images in your mind.

I am no professional, but I see a weeping Japanese maple near the top of the waterfall cascading over the edges to soften the line of the rocks. If you want to do two trees, I think that I would not put them in an even position, but maybe put one at the top of the slope, and another at the bottom corner. Have you thought about how big of trees you want? I think that a redbud, or there are so many varieties of Japanese maples that would do well in your zone. Happy planting. Mary

You're talking about emphasizing the wall and making it even more intrusive than it is already. Much better to take it away.

Definitely.

So far it looks like a beached ship in the existing scene. Probably it appeals because it provides something solid to look at, like a wall or fence behind billowy borders in a stereotype English walled garden.

Key differences there are the wall, fence or hedge is a background rather than a feature, encloses the entire planting.

And it is not cutting across an otherwise naturally contoured bed.

Catkim, that makes perfect sense! I like it a lot, and I also prefer not to be symmetrical. I can start on that tomorrow, with the boulders I already have.

Mary, Japanese Maples are stunning! And they look like the proper size as well. Thanks for the tip!

Bboy, I'm sorry you hate the wall so much! I suppose it's a difference of tastes, but I see your point on the "beached ship" and the need for the wall to be more of a backrop. You've given me an idea though! I bet it would look much better, once having flanked it with the boulders and the small trees, to put a bed in front of it. I wouldn't cut into the lawn, as the slopes on either side of it box it in already (as would adding the trees), and I could use that as more of a specimen garden of sorts, to do lower growing plants that look better from above than eye level. I could also put some things in front of it to break up the view, and some other nice details. Thanks very much for your input!

I don't hate it, it's just a simple fact of design. Slopes cut across by walls do not produce the same feeling as those that have a gentle, uninterrupted contour. Where a relaxed and elegant tone is desired slopes are kept free of bisections and erections. Retaining walls are something we are forced to use were contours are too abrupt to permit them to go unfettered.

Destany~I'm so glad you liked the picture I found! What do you think of rebuilding the retaining wall out of stone, so that there is one consistent material used, for both the pond, and for holding the slope? I'm certainly all for recycling found objects, but I think using just one material would give you more of an impact.

If you can't find a use for the other materials, you might even be able to trade them for rocks or boulders! I wish we lived closer, I have plenty.

I have been giving this a lot of thought, and playing with my photo shop program, I do like what I've come up with.
Bboy, thank you again for your comments. I am sure you know quite a bit more about landscape design than I do and what you say does make sense. I think what it comes down to is that I wanted the slope broken (bisected) for my own reasons, and I also feel it is functionanl as it has created a hard edge for a raised bed that I very much wanted. If it breaks "rules", I'm fine with that.

Prairegirl, I also dislike that 2 seperate materials are used. As I say, with four children, I'm on a tight budget lol. Toooooo tight! I think by incorporating some of the stone to the wall is a good way to tie them together, and I can also use some of the wood over by the pond (perhaps just a small amount, as an edging around the new patio/seating area) will be a lot of help as well.

I'll show what I did on photoshop yesterday, though I'm a bit reluctant lol. I realize this is not the cleanest representation, you still have to use a lot of imagination to see what it COULD look like in a few or more years.

Many of these plants won't work, and certainly would not be blooming all at once or in such profusion. But it is an IDEA of what I am thinking of. I still have a lot of time to research plants that might be similar to this, have the desired effect, and would well for my yard. There is also quite a lot of room in this area to plant a mulitude of things that will bloom/peak at intervals during the growing season.
Anyway...
{{gwi:40124}}

The area outlined in red is where I'm "seeing" a patio of sorts, and the area outlined in purple is the defined path I plan to create. The green area behind, near the fence will be planted of course - I ran out of time.

Bring the bed out around the tree.

Look for a copy of Garden Design Illustrated by Grant & Grant. Reprinted many times, available from used book dealers. Inexpensive, reads like a magazine article. Superior approach to mixed border design described.

I really like that suggestion Bboy, and that book sounds like it would be a lot of help in many ways. :)

I've been playing with window's paint this morning, we really have a lot to do. This yard was completely leveled last year (all of the dirt pushed to the back of the yard as you see, and all previous landscaping removed. But I do love this stuff, and I wouldn't be happy at all if I had a yard that didn't need work!
I already have some clear ideas on the front and sides (the side porch area is my husbands plan, I have no say there) but if anyone see's any glaring mistakes or can offer ideas better than my drawings, I would appreciate the input!

I guess I'm putting these up to show the full scope of the yard and how each section relates to another, and specifically, to the back.

There are several levels to work with. Lots of concrete, sidewalks, steps, retaining walls in the front (made of stone) many sharp angles. Don't ask me why there is a sidewalk leading from our side porch to the neighbors driveway, but it can't be removed. Not only do we share property with them, but we maintain their yard and it helps to get the mowers across.

The yard as it is now:
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As I would like it to be eventually:
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The second drawing... The brown areas are intended to be planting areas. Still not sure precisely which plants or where, other than I want cascading things in the front of the front beds, to come down and break up the facade of the wall which is six feet high. I'm thinking of rambling or ground cover roses, but not sure my neighbors would appreciate the thorns (or keep would their hands off the blooms). I do intend on climbing roses on the side bed though, to climb the porch railings.
The side yard (where the kiddie pool is) is utilitarian - where we put our brush for composting, the hose spigot, veggetable garden, etc. No grass will grow in the middle of this area because there are pipes from the sump pumps in the basement running just under the surface. I intend to mulch it as it's suited for nothing but growing dirt.

Thank you very much for looking, and for all of the advice so far! It is a great help and I think things are coming together very nicely in my mind and on paper.

Quite frankly it's a functional design for your stated needs, but not that aesthetically pleasing to me.

The lawn and bed shapes are not really working towards any unified movement and there are little orphan lawn shapes and bits all over.

Oooooh! I see your point! I think the challenge in that is all the sidwalks and cement leaving the odd squares and rectangles all over the place... Do you think I would do better to have the beds straight and square? I can't removed the walkways, I'm going to have islands of lawn as shown in the top drawing. Maybe I need to approach this with the mindset of tieing everything together, rather than compensating for the rigidness by adding too many curves... Back to thinking...

Try this and see if the form is more pleasing. Instead of a little bump out for the tree carry the bump out over to the stone at the base of the fountain where you have that line of terra cotta dots. Make the bump out for the tree more gradual on the other side too. The bed doesn't necessarily have to line up with the retaining wall

Then on the other side of the retaining wall curve it back toward but only a bit the fence at the back so you have a curve there too. You don't want to go too far back--maybe as far as the level of the retaining wall if you drew an imaginary line across to the fence

Make the bed on top of the garden straight to the fountain.

I would put the walk from the pond to the back door and in just one gentle curve. and lose the little oval beds. I don't think you really need it. If you want additional flowers a grouping of pots on the porch would look good

The water feature is far away and detached from the main outdoor living space, the back patio/porch. That can be a nice destination or get-away, but I might focus some more thought and planning on how you want the patio area to work--what would you like to use it for; is it the right size and shape; does it need other features to make it "work"; does it need plantings associated iwth it to make it more comfortable, and what would those be. Or at least, see how those ideas tie in with the plans for the more distant plantings and paths to the outback areas.

destany, some things that occur to me (not a professional; just a homeowner):

On another thread some time back, someone with an overhead wire problem was mentioning that they were going to pay the utility companies to have their overhead wires buried. I have no idea how common that is, or how much it would cost, but it might be worth investigating, particularly if you have thoughts of adding to the patio roof, or if you need larger trees in the backyard for their shade value.

That's a lovely plan: very clear what's going on. And I like all the different greens. But is it to scale? (For instance, is the distance from house to vegetable garden really three times as far as the patio is wide?) [I can related to the problem: I'd been using my yard plan for a year re. backyard things, then began trying to figure out where I wanted to add a bed near the street. I had figures that just wouldn't work out, and I realized my house is parallel to the street on the west rather than to the fence 35' to the south. OOOPS. Ever try to re-draw a rectangular house at an angle in Paint?]

Do you think you might someday be interested in widening the patio at the back of the house? If so, you might want to consider that in your planning, particularly the location of the path to the potential waterfall patio.

I notice that you're downhill from the rear neighbors, and from all those stairs in the front yard, I assume your street is quite a bit lower than the backyard also. In a heavy rain, what happens with run-off? Did the recent backyard-levelling take care of any problems with drainage?

In your seventh photo, something looks odd where the porch roof meets the main roof. Could some of the flashing be missing?

If you want smallish fruit trees, consider dwarfs or semi-dwarfs. They are grafted to root stock which keeps the upper part of the plant smaller and lower. If you don't find a choice of dwarfs and semi-dwarfs in your area and you aren't fazed by mail-ordering bare-root trees, consider Stark Brothers Nursery (Louisiana MO), Raintree Nursery (Morton WA), or Miller Nurseries (Canandaigua NY).

destany:

Starting over--
go back and look at the first photos you took. I see an astheticly pleasing natural line for a flower bed.

Look at photo number 3 can you see the line going back from the pool, right where the shadow from the telephone pole bends. Follow that line and it comes out in front of your retaining wall and back at the other side of the wall.

Now go back to the first one. Have you ever thought that the space on top of the retaining wall would make a nice shady spot for a small patio and bench, The natural space to put a step would be at the indent in the wall. I can see a step and flowers on both sides of the step and a patio center and towards the right side. This would balance the fountain on the other side, and having the step breaks up a long straight flower bed

This plan would give you gently curved beds and the bench would break up the expanse of plantings the patio would also give you access to weed and things in there.