You haven't said the house is symmetrical, and even if it is you don't need symmetry but rather balance. I'm not clear on why you've chosen to divide the yard into "designed" and a "plant collector's" halves. You can design with special plants, integrating the two objectives. And you wouldn't be the first one to begin your design process with the plants you have or want. But what does catch my attention is the word "perennials". It may have escaped your attention that there are a lot of very special plants to collect in families like conifer, Japanese maple, and rhododendron ( you may curse me when you find out how much money can be spent on those plants :-)). I frequently recommend that people take a spin around the conifer forum to get an idea of the world of dwarf conifers. I started with perennials too, but am finding them much less gratifying and less amenable to being designed with as my interest in overall landscape has escalated. What you're after with plants like that is "bones", which is something you can do with hardscape as well. To post a photo, you could check out the gallery side, and put a link to it here in this thread, or you post from a Photobucket or other photohosting site. What you want to put into the body of your message here is the html code, starting with something like KarinL

It's a very nice looking house, and for once the builder has made the path fairly wide, and left more than the usual measly 2 foot planter between house and walk, so you are off to a good start. I'm sorry, but I don't know a thing about trees or shrubs for your zone, and beyond that I am a complete amateur, so I thought it better not to comment and pass on possibly bad information. Perhaps you can stimulate more conversation by talking about a "look" you might have in mind? Ask about specific trees you are considering? Are you an avid gardener or are you looking for something that will be maintained without much effort? Do you need a grass field for the kids or are you looking for masses of flowers? Narrow things down a bit and folks will offer ideas. You did ask about low and airy bushes, which here might include certain salvias, pentas, or agapanthus, but I don't know if they will work for you. Things have been slow here in general; don't give up.

There are three rules in landscaping. Thriller, Filler and Spiller. For the thriller, you want something that will give height to the yard and add some color. You might consider picking something that blooms with brilliant flowers for some of the year. I would start in front of the house, and pick taller bushes that take away a bit of the white space, but don't cover the house completely. I would center them with each portion of the house they will be sitting in front of. For either side of the front porch, and on the corners of the house, choose something even taller. Go with something that adds symmetry and gives the feeling that it frames the house. A taller tree may be a good choice for the corners of the house. Next, choose a filler. This can be comprised of many different types of plants that will spread out but remain short. Choosing a mostly green option is good, but don't be afraid to add in flowers as well. These will add additional color to the house and will compliment the thriller. Finally, pick a spiller. The spiller is especially great if you choose to put in flower beds that had a solid face at the front. This may be a good option for you since you have a fairly flat front elevation. You could do flower beds like those you have in the backyard, which have a plain front but add height. The spiller is a plant that will fall over the edge of the bed and break up the solid face of the bed. It adds visual interest, and if maintained and trimmed occasionally, it will not look messy or unkempt. I do not know what your house faces, but if it faces a street, you could consider putting in a stone or concrete path that would add an additional element of visual interest to the front of the yard. If you do choose to add a path, you can line it in plants of varying heights (Not taller than 18 inches). For around the side of the house, you can add higher trees or large bushes to fill in the sides of the house and frame it. Refrain from adding tall trees in front of the house as you don't want to hide the house from the street. Hopefully this helps...!

This is my comment on a Dilemma from earlier. The links may be useful regarding deer, but they will not work directly from the snip; you'll have to type them in to go there.