On my main box (with good specs) I have winXP
On my shabby old box that used to run Win95 (sluggishly) I have Ubuntu. However, I need to get rid of GNOME and replace it with something less demanding like Fluxbox...
I would like to try Gentoo, but I suspect it would take forever to build on my crappy old machine (4Gig HD, 128MB RAM... 300 MHz Cyrix processor...)
This setup is not my choice- this main comp belongs to my parents
If it were up to me it would be a dual boot machine (so I could have Ubuntu on a decent computer), but I'm too worried about accidentally deleting everything- got no way to make a backup...
I also have a Linux Live distro (Feather Linux) running off my USB pen, with the appropriate boot floppies for more stubborn computers (like the school ones). I plan to remaster this to suit my needs better sometime. (maybe two- art and office versions)
So I'm fairly well equipped as far as OS are concerned
and to junker- I would recommend Ubuntu/Kubuntu (only difference is the desktop environment, respectively GNOME and KDE). Very easy to install, decent documentation, and a friendly community. I got it installed first time in just about 2-3 hours, no problems
And if you are trying to get dual booting with your current OS, I would definitely recommend that you know what you are doing. Read some guides first