Right now I'm posting on my laptop which is running Xubuntu GNU/Linux. I dual boot my desktop with XP and Xubuntu and at work I use XP. I spent a couple years in college using nothing but Debian GNU/Linux but my job requires Windows and I'm also into PC gaming.
I've been considering getting a Mac book which I will probably triple boot with Windows and Xubuntu.
I've also considered setting up a GNU/Hurd system for a couple years now but have yet to get off my lazy ass.