The big buzz is the apparent release of Vista Service Pack 1 but I say who cares? Not me that's for sure. I do run Vista on my business workstation but I'm in no hurry to download and install it. I'll let some other idiot download it and stuff up their machine before I do it.
Look, as far as I'm concerned Vista has been a total waste of time. No client we have wants it, most clients specifically tell us 'don't give me that F*&^ING Vista' and personally I tend to agree. Vista is SLOW, it consumes so many systems resources that you need at least 2GB of RAM to make it work with any application, the interface is all different and heaps of important things are now in different locations. By and large it is a pain.
It was even more of a pain until I disabled the Aero interface and all the advanced features so it would run quickly. Now my desktop looks as boring as Windows 2000 and it still isn't even as quick. So without the Aero interface why the hell would you buy Vista unless you had do? I expect after Service Pack 1 is released Microsoft is going to make it harder to obtain XP since for many Service Pack 1 is the theoretical point at which they install Microsoft software.
So if you look at it pragmatically, if you have Vista (sucker) then I'd wait and see what other people find with Service Pack 1 because I'm sure it is going to cause some issues and let me tell you that you don't want to be the first to experience that pain. If you have Windows XP (lucky) then I'd say hang onto it with all your might because it is probably the fastest "supported" Operating system Microsoft currently has.
So whether you have Vista or XP I'd just get on with what you're doing and let Vista Service Pack 1 wreck someone else's system.