I've learned Linux when most of my friends at college started using it (they were mostly Computer Science Majors). So I've used slackware, redhat, and a few others. On my own computers I've installed redhat, college linux, ubuntu, edubuntu, Movix (which fit on a CD with a video file), and a few others. Right now I have an ubuntu install that won't boot and I haven't taken the time to fix it. Mostly I run off a live CD if I want something.

I do run portableapps off my iPod. GIMP, Open Office, Firefox, Pidgeon and some other programs run off the iPod. No install necessary.