Until Crysis actually comes out and gets reviewed under the different cards, again, no one knows for sure. Some of the early reviews that have only measured 3DMark scoers, the 2900 XT with GDDR4 has done better, but that's a synthetic and not a real game.
Nvidia does have a number of Vista problems, the most notable being its troubles with SLI. As a single card, its done well enough. No one knows when, if ever, the driver troubles will be solved. Its possible that there's an inherent problem in the design that will only be cured with the next line (8900?) of Nvidia cards. But that's speculation and nothing else.