Yep, a few days ago I went down to MicroCenter and bought myself an HP Pavilion Windows XP Media Center computer and brought it home to replace my Mac mini. And when I get back to work this week, I'm going to request a new Windows computer to replace my PowerBook. I tried living in the Mac world for the past year (I got my mini last January) but I just can't deal with not being able to be on the bleeding edge anymore. As my list of new Windows software that I wanted to use grew longer and my frustration with the Macs lack of power and speed as well as the exorbitant hardware prices grew more intense, I decided that I couldn't deal with it any longer and made the big decision to swap back.
I've been feeling this myself. I'm going to wait it out though. I don't want to buy a laptop right now, and regret it when Vista, or OS X (x86) come out. My list of software isn't that long either so I can afford to wait.
And in my case, I'll be switching to Linux/Windows.