I stuck with XP when Vista came out with so many complaints from users. Even after Vista matured somewhat, it still didn't appeal to me. Windows 7 has, in my opinion, turned out to be a "horse of a different color". I was impressed enough with the RC that I decided to build another machine dedicated to the OS. (I'd evaluated the RC in VM on an XP box) As a member of MS Technet, I d/l 32-bit Win 7 Ultimate to install on the new computer.
Since the build, I have been slowly turning over production duties to the new box. I also continue to run a production XP machine next to it, and switch back and forth as needed. It will take time to get everything just right, but so far, I'm pretty happy with it.
Always code as if the person who ends up maintaining your code is a dangerous psychopath and knows where you live.