I somewhat doubt, that given my oldie HW are any of these any relevant anymore, but I do play:
World of Tanks (not much after the v9.0 patch)
Need For Speed Porsche Unleashed
Tetris ( http://www.mediafire.com/?o1ujhfhqmxua427 )
Hope this list is hepfull for well… anything
Hawken (Free to Play): http://www.playhawken.com/
It uses the Unreal engine 3 and it is pretty fun. It is a mix of FPS and Mechwarrior.
Graphics on high make the game nice to look at. Needs a good PC to play as the game was developed on i7 cpus and GTX 580 gpus.