I have the Geforce 256mb 6600 and it's a good card but getting a little old. I would definetly go for the 6600GT. Even better go for the 6800, which are coming down in price all the time. There are alot of them out like the GT, GS etc. I'm not sure which 1 is better but I have heard good things about the GS. But if you've got a PCI-E and can afford it go for the 7800GT.