What operating system do you use? Which operating systems have you used? Why do you use your current operating system over others?
Primary OS: Win7 x64
Secondary OS: Ubuntu 10.04 (will probably be replaced soon)
Tertiary OS: Ubuntu 9.04 (will probably be replaced soon)
OSes used:
Win: 95, 98, ME, NT, Vista. Note: I have dabbled with XP but not extensively.
My primary OS is used for Urban Terror, Ventrilo (though Mangler is pretty darn sweet), general web surfing, IM, and music.I choose it because last I heard, you need iTunes to sync your iPod Touch because it runs a modified version of OS X (iOS). One of the things that makes me not able to go back to Vista is the way the taskbar is. No longer need for a quick launch, and the pinning is really intuitive. It's really hard for me to go back to a system without it. Not that I hated Vista--I liked vista just fine.
My secondary OS hasn't really been used much. It runs the xmonad DE and occasionally GNOME. I use xmonad because it really /does/ save a lot of time when you're programming. Also, it helps if you are learning from a website and don't need pictures, to just boot up Elinks. I use GNOME because my experience with KDE has generally been bad.
My tertiary OS is just kind of there. I haven't touched it, really, since before I left for school last year. I am currently using it right now to attempt to create a mirror of two manga websites.
Future? I am going to try to install Arch Linux as my secondary OS on my main computer (my laptop dual boots Ubuntu and Windows and is currently my most powerful system).