I know I am a bit late here, but I was out of town for a few weeks.
I run dual 2560x1600 screens, which is even more pixels than what you are looking for. Currently I am still on 2x 6950's which is working well. One drives each screen though I can (almost never do) enable crossfire if needed. I run almost every game I currently play at pretty much max settings and dont have any framerate issues. About the only issue I have is getting scooted up too close and missing things on the edges of the screen (its a real problem that has gotten me killed more than a few times...).
I believe from another thread you are running a 570 which should be just fine for that resolution. Just remember, you can only drive one dual link monitor per card (for most cards, something silly like a 690 can do 2), so if you plan on running a second screen I believe you will need a second card. I could be wrong, I havent tried to connect anything but my 30's to my machine in a couple of years.
The ratio comment by the other poster is correct, misleading at first glance, though I do see the point behind it. You can always drop down to a lower resolution keeping the aspect ratio correct and have a decent experience. However, coming from someone who has used high res monitors for years, you really wont want to. It sounds good in concept, but when you sit at a large screen while dropping the res (keeping the aspect) it just doesnt feel right.
After all that, my only other suggestion is if you are going to drop that kind of cash on a monitor anyway make sure you are getting the largest one you will want for quite some time. 27's are nice, but the price difference between them and a 30 is not that much (if you are in a position to drop that much on a screen anyway) and the 30's are slightly higher res yet. It really depends on your situation though, a 27 may fit your needs perfectly.