Best resolution I'm guessing is 1280/1024. Your getting a PCI-E MOBO? If you are then I would suggest the x800 XL. If its AGP, then the 6800 is your best bet with your budget.
Whats the best overall? The PCI-Express mobo will cost me about the same as the AGP mobo. But the PCI-Express card (x800XL) is much cheaper than the AGP 6800GT. WHat to do? What to get?
Get the x800XL then. It performs well in alot of games such as farcry/Half life 2, and Counterstrike source. The only game it sucks at is DOOM3, but It will perform at the same level as the 6600GT with doom3.