7800GT is falling in price so fast because of the 7900GT on the horizon, which is going to be roughly as fast as 2 7800GTs in SLI. That should put the 7800GT around the $200-250 price range and the 7600GT around $150-$200. Since you are okay with 1024x768, you couldn't go wrong with either the 7800GT, 7600GT, or 6800GS, all of which are designed to scream at that resolution in today's games.