Ditto, what Cleeve said, the GF7600GT will smoke them both and then some for games. And as for portending to the future, just look at the HL2-HDR, BF2, F.E.A.R. and Serious Sam 2 results, all could be considered future-facing games, and the GF7600 just walk alway with it by double digit % gains.
The only exception IMO is for 2D video where ATi's AVIVO is nice. But in this case I'd make an exception to my usual missives about 'magic future drivers' and say that the gaming performance benifit of the GF7600GT is worth the risk of the promised improved PureVideo drivers (and the promise they'll be FREE finally).
Definitely the GF7600GT for PCIe, solid bang for your buck, and in no way 'crippled', which is more than I feel I can say about the other two cards.