I got the 6800GS last week and I'm impressed with it. FEAR does play at high settings, yes, but Smooth Shadows still knocks the hell out of it I'm afraid
So I still have to have this off. other than that, I get a rather high FPS.
Your best bet if you can afford it is the 7800GS which is rather cheap, and I would have got that if I had the money too
The only real difference between that is the fact that it can handle 8 shader instructions per shader, compared to the 4 of the 6800GS, but that does make a bit of difference, and will for later games, even if it does have less pixel pipelines than its bigger brother.