Why do people suggest 6600 gts . I have 6800 Ultra and let me tell you IT SUCKS SO BAD. I would take regular x800 over it any day.
People say: oh it supports shaders 3.0 well if getting 5 fps in splinter cell with shaders 3.0 enabled is "supporting it" than get an Nvidia, but if you want a good video card get an ATi.