Laptop & desktop are running Ubuntu 8.04. Technically I'm running the Ubuntu Studio version. Both also dual boot XP just in case I to do something Windows related. I still have an older machine running Win NT 4 service pack 6 but I couldn't even tell you the last time I booted that one. There are 10 running machines in this house and only two run Windows on a regular basis. Heck there are emulators that let you run Windows INSIDE Linux.
There are several Linux variants that are good. Ubuntu and Mandriva are two I'd recommend. If you've ever used Mac OS X the gnome desktop isn't much different and it's very customizable so you can tailor it to your liking.
BeOS has been discontinued for a while now, but there's an open source project based on it called Haiku that's alright.
Here's a shot of my desktop that I saved a while back.
