Lisa...I think in your kitchen you could go either way. Regardless of where your (main) sink ends up, it will still be close to the cooktop & you will have room to prep b/w them. If the sink moves to the refrigerator wall, you will have even more prep space b/w them. While a prep sink would be nice, I don't think it's a necessity to make your kitchen work. Yes, it would add an additional prep area for you at the island (b/c there will be a water source) and, possibly, reduce some zone crossing, depending on the location. Right now, to get to the refrigerator from the cooktop you have to either cross the Cleanup Zone or go around the island. How many people will be using your kitchen at once? Will they all be prepping/cooking or will there be a mix of prepping/cooking/cleaning up? If cleaning up is in the mix, then the zone crossing could become an issue, especially when the DW is open. As to location, I like Elizpiz's setup best, but I can see where it would definitely reduce available counter space. If you put it on the left side across from the cooktop, it would be readily available from the cooktop as well as the "outside" part of the island for prepping there while someone else is cleaning up on the "inside" as well as be available for outsiders for a drink of water, etc. However, it will reduce that 42-1/4" to approx approx 24" of workspace directly across from your cooktop; but, as I mentioned b/f, you will still have add'l room on the wall run. If you put it on the refrigerator end, I think you're right in your assessment...I find that I use the counters across from both my refrigerator & ovens much more than the counter next to them...both for removing things from them as well as staging things to put in them. (I have approx 32" b/w the Ref & DR peninsula end and approx 44" b/w the ovens & the end of the "mini peninsula". Both have landing space right next to them as well.) We do have a prep sink, but in our kitchen it was a necessity to make it work. Our cooktop & sink are opposite each other, separated by approx 6'6" of aisle...the main aisle through the kitchen. By adding a prep sink on the cooktop wall, we were able to separate the Cleanup Zone from the Prep & Cooking Zones as well as protect both zones from kitchen traffic (inside a "U" w/short legs but long base). During the week, there are usually two of us in the kitchen...one prepping/cooking (me) and one cleaning up (DH) with an occasional child helping make veggies. On the weekend, there are sometimes all four of us working in the kitchen! When baking (usually a marathon!), there are usually two or three of us. (I seem to bake in spurts...when I bake, I seem to go all out!)

Green Designs came up with a great plan, as usual. It's very similar to my new kitchen. The aisle between my 9' island with prep sink and the rangetop wall is about 42" counter to counter. Its perfect. I've had much larger aisles and hated them. In fact, that's one of the reasons I reno'd my old kitchen. I'm the sole cook in my kitchen 99% of the time, and I would never, ever, ever give up my prep sink. Ever. I love having a large prep zone with a dedicated water source that I don't have to share with the cleanup zone. I'm usually the one who does the dishes too, but when DH occasionally does that when I'm cooking, he can do it out of my way. This kitchen is my first experience with separate prep and cleanup sinks, but it has changed my cooking habits and way of looking at things in the kitchen. You will not use the sink on the perimeter to prep the way you laid out the space. It's not convenient for daily prep. It is a great place for a cleanup sink. Being over on the side like that, your dirty dishes won't show much. Mine don't. Between the giant single basin cleanup sink and the perimeter location, the few dirty dishes waiting on the counter for the DW don't both my OCDness very much. And as you can see, my kitchen is open or at least semi-open to all the other rooms in the house and to the front door. I much prefer an island being all one height rather than bi-level. Your first inspiration pic island is one height. At one level, you can spread out for large baking/cooking projects and for school, sewing or crafting projects. A large kitchen doesn't have to have wasted space. It just needs to be laid out correctly so you have the right amount of space in the right zones. I agree with everything Holly said. I think you could have a great kitchen here!

Your disposals could also be partially clogged. When my DW is backing up in the sink, I turn on the disposal for a moment and it starts to drain. Cleaning the disposal periodically by running a dozen or so ice cubes through it helps to keep it clean.

@C. First of all, if you are 5'10" and have really bad back pain, then a 38" countertop height might still be too low for you. I'm barely 5'7" when when standing up as straight as I can, and a 38 3/4" countertop height is very comfortable for me. At 5'10", you could easily go up to a 40" countertop height. It is uncommon for kitchen designers to specify countertops much higher than 40" for anyone except a frequent kitchen user who is taller than 6 feet in order to retain the general usability for varying heights of potential users, but you may always do what you find best for yourself. I would encourage you to do a mockup of a 40" countertop height and try different tasks like chopping on a cutting board and stirring in mixing bowls to see how you like it. Remember that you should allow 1/2" for cabinetry leveling, so find your perfect height, and then subtract 1/2" (from the total of cabinetry plus countertop) when placing your order. The minimum possible front countertop ledge width is determined by factors which contribute to the risk of a break. I will guarantee you that ledge width in your picture is probably wider in person than it may appear here. Few fabricators will cut a continuous ledge (meaning without seams) less than 2 1/2" to 3" wide, and some fabricators will even burden you with a 4" or greater ledge, though that is excessive. The Galley issues guidelines for cutting the sink hole with no seams around the hole, but this technique complicates the handling and transport of the piece because that area is so delicate once it is cut. If I understand, correctly your countertop will only be 1/2" thick which may mean that you are using porcelain or something of that nature, and in that case, the substrate will dictate that you will need a seam for a narrow front ledge rather than having the sink cut from the middle. Porcelain is already fragile, and it won't survive the handling, transport, and installation with a pre-cut, narrow, continuous sink ledge. Be cautious of any fabricator who wants to install steel rods to help stabilize a front sink ledge. Those rods can get wet and swell and cause future breakage. The best policy is to avoid rod reinforcement. In terms of ergonomics, the height of your countertop and the height of your sink is relatively more important than how far forward you stand to the sink, but if you have really bad back pain and want to give your best effort to eliminating that in your kitchen, then an apron-front sink still needs to be on your list for consideration. I regularly operate within the full confines of the apron front which brings dishes and other tasks such as cleaning the sink very close to my body and allows me to stand mostly upright. It is the leaning forward at a sink that strains your back, and you will lose at least a hand width's advantage with a non-apron-front sink of your ability to work closer to your body to minimize leaning. For many people this is not an issue, and due to the fact that non-apron-front sinks are usually less expensive and more plentiful in terms of brands and styles, plus more aesthetically pleasing in many instances, the majority of kitchen remodelers are not using apron-fronts. Both Rachiele and Havens offer texturing for their stainless steel sinks, and if you look at their portfolios, you'll see that a hammered or otherwise textured finish is actually very pretty for an apron front sink. I have a textured finish, and it hides water spots and scratches and it looks as new today as it did several years ago when I had it installed. My only caution is that the interior of the sink should preferably be smooth to aid with cleaning. I believe that texturing can be applied only to the forward-facing and top ledge part of the apron front if you like that look. Spillage over the apron front is not a problem for me. Every now and then, I might get a small drip down the apron front, maybe after loading the dishwasher with something wet, but nothing more than you would sometimes get from a sink with a ledge that gets water on the front ledge and drips down occasionally. I would be hard pressed to say if I even have to wipe drips of water off the apron front even once per week. It just really is not a problem for me. It sounds like you are on the right track to helping with your ergonomics. As I mentioned earlier, your first step is to see if you can raise those countertops up to 40". If you do a lot of bread kneading or something where you need your arms straight down, you might consider doing dual levels somewhere in the kitchen. Generally, 41" to 42" is the upper stretch of a modified countertop height, and that would be for someone taller than 6 feet. The reason that we don't like to raise the countertop much more than that is because then they become unusable for people who are shorter. However, at a height of 5'10" with back problems, 40" is not at all out of reason. Be aware that if you wear shoes with thick soles when you are working in the kitchen or if you intend to put down a comfort mat on the floor that has substantial thickness, those factors could alter how you feel about your cabinetry height. Mocking up a height and doing various tasks is the most reliable way to determine what is best for you.