Nope. Shadowrun came out on the 360 too. And Crysis runs under XP.
There are games that play better on the PC or that run with a little bit more eye-candy under Vista, but most of the gaming reviews I’ve seen say that they get much better frame rates and sometimes better stability under XP. Sad, that.
Yeah, if you’re seriously into certain genres of games, you might want to deal with the Vista headaches to get the good stuff. Most RPG, RTS, other strategy or sim games aren’t hugely resource-intensive though. High-end FPS like Crysis can benefit from the improved video support in Vista. If that’s your priority, you probably won’t have a problem with spending 3x or more what normal people do on hardware and will be willing to do the tweaking necessary to make things run well. However, most people would probably be better served by either sticking with XP or buying an Xbox instead.