Well i would say get a 6800gs, but u need to give more info in ur post.... like tellin us wats ur budget, or telling ur personal opinion, and the brand and info on the card.
(it could be 512mb or 64.... we wouldnt know)
But yeah..... the 6800gt would be best, if it has 256mb memory
DONT GET 128mb
If any Nvidia cards second number is below 800.... dont get it
For example... a 6600 is WAY better than a 7300
I know its confusing, but its true