Go for the 8800GT. Its probably worth the extra cash for DX10 support.
Not that graphics cards that are DX10 ready now, would be with future games that'll need more polygon pushing power, but yeah...
Yeah, thats what I kind of think with Dx 10 cards at the moment, and I know I won't go to Vista, but still, you have the support (that you probably won't use in the cards life time), but also more polygon/effects power.
