If you've got that kind of dough to toss around, sure. But I wouldn't.
While the 8800 is the current 1000 pound gorilla, it's still big and hot and power-hungry. While it is the first DX10 card, DX10 ain't out yet... and neither are decent Vista drivers.
As for me, I'd look at a X1950XTX, a 7900GT, 7900GS, or a 7950GT if I were going for high-end.