As usual, with any new Microsoft OS, there's plenty of growth required to make it work, but it seems like even with the continued delays in releasing Vista, there's still lackluster support. Drivers aren't fully ready for Vista (though XP had the same issues). Vista's security is also still a mess, and forget anti-virus support for the time being. I'm amazed after al this time in maturaition that Vista is still not fully baked.
Honestly, I can't think of a better time to consider Linux for your XP upgrade. It's the perfect way to get off of the Microsoft treadmill, and it's stable to boot. Hey, even IBM wants to help you move to Linux. Remember IBM? They had that PC OS that was clever by half or something, but they're really on to something. Heck, send me an e-mail and I'll help you out as best I can. There's also some excellent books to help you out.
But, you'll continue to buy, won't you? You'll continue to run Windows because it's convenient. After all, convenience is comfortable.
Comfortable like a straight-jacket.