just to jump in here real quick.
I have to respectfully disagree with you on the 24" monitor statement theyarecomingforyou.
"For a single 8800GTX get a 22" widescreen"
I've been running my 24" Dell 2405FPW for several years now... and I wouldn't trade it for anything! (ok, except maybe a 2407FPW) I'm only running a 7950GX2, and I run my games fine.
In every situation, I can run a game the way I want at 1920x1200 with a little AA, or 1680x1050 w/decent AA quite well. My roommate has a 2405FPW on a 7800GTX, and he has no problems either.
The size and resolution come in handy for me so often that I just can't see working/gaming without it.
It also has the convenience factor of having tons of inputs, including tv inputs, which come in handy when working on tvs, pcs, xboxs, etc. When my buddies come over for a quick xbox lan, my 24" monitor instantly becomes a damn handy extra tv.
maximus0402, make what ever decision you want, but just know that an 8800 GTX will push a 24" monitor JUST FINE. However, your hopes of "be(ing) able to run on max settings for now and future games in the next year or two" is just unfounded and won't happen. Even if you buy a 17" lcd with a max res of 1280x1024, you won't run every game for the next two years at MAX settings. You just WONT. Software will always push the hardware envelope in a way that will keep the hardware humble.
With that said, you should have no problem running your games VERY NEARLY all the way up. There's always a happy medium when it comes to graphics settings, a give here, take there kind of thing. Something you have to remember (or clarify) is what "MAX settings" really means. That means very different things to different people. And with the games adding more technologies all the time, there's more and more for you to consider when "maxing out" your graphics settings. Games now-a-days have shader, physics, aa, texturing, shadowing, fog, draw distance, Diffuse, Bump, Specular, AF, (etc) settings, and keeping them maxed out will always be a chore. But finding a mix you're comfortable with should be very easy to do with an 8800GTX (at 1920x1200) for several years.
Still, I would say opting out of getting a 24" monitor simply because you can't blast every game out of the park at 1920x1200 for the next two years is pretty foolish, in my opinion, because it's simply not going to happen anyway, regardless of resolution.
Something else to consider is if you are that concerned with getting the most insane performance possible, wait a few more months for nvidia to unveil their new gpu line that should hit sometime this fall, or maybe winter. As far as SLI goes, I PERSONALLY don't think it's worth it. It certainly has it's performance advantages, but I just personally think those advantages come too little too late too much of the time. This is because SLI is so very driver/software dependent. This is normally fine when your cards are new, as your equipment is their flagship product and keeping the support up is paramount for them, but once your card is a generation old, support for you goes on the back burner behind the new king, and you often won't find proper SLI support for the newest game you just bought for weeks or months. And then, in the end, unless you're trying to push insane graphics at insane resolutions (2560x1600), the gain you might eventually get will only really apply in that ultra high end space. And personally, I don't think being in that space is worth the cost of entry, and then the on going cost of searching for sli profiles/settings that work best for that newest game that 'doesn't have native support yet'. Again, this is all just what I've seen from my experiences. Your mileage (and tolerance) may differ.
My X2-4800+ and 7950gx2 still pushes my 24" quite well... better than I could have ever hoped for considering how long ago I bought them. I don't think you could possibly be disappointed in your purchase either.