My main system is running FreeBSD 5.5, I guess you might still call that alternative. I actually do pretty much everything with it, i.e.
- office stuff with OpenOffice, Cups, laser printer
- web browsing, mail, irc, chat (Opera, Firefox, GnomeICU)
- audio / video streaming and playback (Mplayer, XMMS)
- some games (mostly MAME, some 3d games like bzflag)
- graphics & photo editing (Gimp, Xmorph)
- 3d stuff with Art Of Illusion, Blender
I also have a Windows box, but the only purpose of it is running Cubase. I have several other boxes, e.g. a SUN Netra server and lots of retro computers, including several Amigas. The Amigas are used for playing games and for keeping up to date with the development and latest aminet stuff. At the moment, I'm trying out some NetBSD cross-platform devevelopment with my desktop 1200 (030). Currently, I'm trying to get my WLAN card to work under NetBSD (works perfectly under AmigaOS). My Amigas are also used for some productive stuff like IRCing, burning CDs etc., but most is done with my FreeBSD system.