I'd love to try running linux, just to chicken to try it on my only computer. If we ever get another computer, I'll try it out on the old one. I use to play around with one of windows alternatives several years ago. It was freeware, can't for the life of me remember what it was called.
It is very well done.
You can try it with out installing it on your hard Disk....
Multiple window managers ,...KDE, Gnome, XFCE, LDE ....32 bit or 64 bit versions.
You can always just download a 'live' CD. Most distributions have them available. You basically boot your computer off the CD/DVD and can try it out. If you find you don't like it, you can just pop out the disk, reboot, and *poof*, you're right back to your old PC.
If you want to try Linux, I’d strongly recommend that you get VMWare player and install it there. Once you have a distro installed in vmware, you can even make it full screen, and you can’t tell the difference from running it on bare metal. I use VMs a lot, though I went ahead and purchased Workstation. Player if free though, and you can install as many VMs as you have disk space for.