For that price, I'm not sure you could get a card that would run games at decent settings/resoloutions at all,
but you could certainly find maybe in the 5000 Nvidia range, like the 5800 above, a good gaming soloution if you don't want to run at high resoloutions or settings.
Though, even then, especially with a new game like F.E.A.R or Stalker when that arrives, the GPU takes a dramatic hit.
You'll find with the 5000 range, even though they are built to run Direct X 9 games, they can't run in that setting very well, and so some games like Half Life 2, force Direct X 8 on the card which then speeds it up.
If your lucky, you might get a card (not really for that price range though) that will last you a year or so.
I'd advise to save up though for a Mid Range card like the 6600GT on AGP.