I just installed WinXP last night and love it so far. I don't have any experience with Linux so I can only compare Windows platforms.

I have to say that my old school favorite is definitely DOS. I was pissed when they made Win3.1 - for some reason it was so much more tedious to use at first than DOS. I always go back to DOS when Windows is acting retarded. WindowsXP is the best Windows OS though.