Won't work.
As of this past Jan 30, all BestBuy, Staples, etc. outlets have NOTHING BUT VISTA for sale on new computers. XP retail CDs are going like hotcakes because folks like us know XP is doomed within another month or two.
Face it, Vista is the future of PC computing. Microsoft is not going to be hurting at all.
I've got a Linux (FC4) box, and a Mac Mini (Tiger), and a Windows XP-Pro box. (Vista might run on the XP box, but I'm not going to find out.) Linux is my platform of choice.
So what. Look, we're in the vast minority. Within one year, Vista will have taken over 40% of PCs, and within two years, nothing but Vista will run the latest software being sold, and it'll be on 75% of PCs.
I hate to say that, but it's gonna happen. Prepare your alternatives now, if it's not already too late.