Game performance is another thing entirely - personally I think this is driver related (we should be in a better position by shipping date) and DX10 should have a performance jump again (as it's more efficient).
Fortunately, it's not as if Microsoft touted Vista as the Windows for Gaming, so we can't really blame them for it sucking so bad for games.
Unless every single dev stops making games for XP, I'm not switching. I fail to see a single benefit in Vista. Ofcourse, MS's monopoly will simply FORCE everyone to switch, yet again.