The_Prophecy suggestion is great but as far as the DX10 cards go, there are currently two available. The Geforce 8800GTS and 8800GTX, both completely blow the 7 series out of the water in even DX9 games. Just check the reviews and such...
I would suggest going with a 8800GTS (here
) over the 7900GT. It's $204 more, but in some situations can outperform 7900 SLI configurations on it's own.
Just my $0.02
Edit: Oops, pasted wrong link