Assuming you can afford the following cards, they aren't bad -
-<<(1)>>--<<(2)>>--<<(3)>>-Don't be fooled by the name of a video card. Generally, the last three digits tell you what the card is for. 300 and below are for office work and applications, 400 and 500 are for fairly light gaming, 600 and 700 are decent gaming cards, and 800 are for serious gaming.

So, for instance, a 6800 GT will perform better than a 7300 GT in terms of gaming. The first digit of the card's name tells you the generation.