"I am running a 7900gs on a Dell 24" at 1920x1200 and it does well enough to play most games decently. The 2900xt is much more powerful, so I'm sure you would be fine."
Exactly. Which was pretty much my earlier point about the 6600GT. I would think that gaming usage was as much implied in the question as it was my own comment. Had I gone on to what plays at what FPS etc it probably would have sent the thread off on a major digression.
But if it helps: In a nutshell, most of my games are still just playable on higher settings, albeit with only low AA and AF, which is OK at that res. Not the latest titles obviously, since CPU is then more the limitation on my rig, but HL2, Doom 3 and UT2004 and others mostly run fine (UT especially). For eg. one I did check that ran at about 70 FPS average at 1280 x 1024 dropped to about 40 on the new screen.