Anything around 40FPS is good playing as far as most of the world is concerned. And when you're playing at 1280x1024 with 4xAA and 16xAniso, what more could you want.
And a new generation is GeForce 6/7/8 etc, or Radeon 9000/X800/X1000, not GeForce 7800GTX or 7900GTX.