Being on a budget sucks, but being able to find an excellent deal is great. The 7900 GS KO by EVGA is a good mid range graphics card that is sure to stay good for at least a year or so.
Although it only supports Direct X 9, it should still be able to run games released in the future while already running current games a steady rate. When attempting to run Crysis, with all settings set to medium and at a resolution of 1024x768 it runs reasonably well at an average of 26 fps. Unreal Tournament 3 on the same resolution and same amount of detail runs at around 30 average. Call of Duty 4 runs at an average of 40 with most details set to high and Gears of War PC runs great at around 50 fps with all settings set to high. Half-Life 2 and its expansions average at 60 frames per second with 4xAA and 16xAS.
My only complaint with the card would be the fan. It is impossible to control the fan speed with the current Nvidia EVGA drivers and will always run at a 79% speed. When a game is being played, or a movie is being loaded, the fan will run at 100% capacity and is very noisy.
the 7900 GS KO is a good buy and is most likely a lot cheaper now since I bought it a year ago and it can run all the current games reasonably well, and run older games like a beast.
*for reference I ran this on a 3.4GHz Pentium 4 with 3 gigs of ram (don't know which kind sorry)