You can still buy XP

If Windows Vista is giving you fits, you can still buy Windows XP from Amazon. (And put a little coin in my pocket if you use these links.)
Windows XP Home Edition
Windows XP Professional
We used XP Professional on my wife’s PC before it gave up the ghost, and, having used Vista on the Dell we bought to replace it, I sometimes wish we’d stuck with XP Pro.
At least I spend the majority of my time in OS X