I am on a win95 machine right now. It's my only link to the outside world from work. Mostly it's just suppose to be just used for running a 3270-type terminal emulator and e-mail, but my boss doesn't mind me surfing around on it. Besides that I don't use it for anything.
It's been a long long time since I had Windows installed at home. I lost all my installation media I got from school a long time ago. I went to go get win2003 for free, but it was a bit of a hassle and I forgot about it. My laptop had win2000 dual boot on it for a while, just because I got it with the thing. Got rid of it for the extra disk space. That sort of thing.
I wouldn't mind having a windows installation laying around, I am not that bigotted. But I probably wouldn't use it outside of fooling around on it.