What OS do you use?

I use GNU/Linux. When I started on pixel art, I wasn't a serious artist (I'm still not) so I didn't have any of the expensive proprietary programs. Pirating was out of the question since I didn't even have broadband. Then I got disgusted with windows and waited several weeks to download my first Linux distro, mandrake 8.2 (I think it was) Once I found the GIMP, I didn't know how I ever lived with out it.