Linux is an OS based on unix. It is quite secure and really meant to be a server OS. It is slower than windows as a desktop os, but if you get a couple people all accessing the same thing on one machine and see who is faster(-: It is extremly cutomizable. If you want it to do something, there is likly a way to do it. If you want it to look a certain way, you can do it. There is definatly less support for linux, but much of it is open-source and free. Games are slowly comming along. I have found linux to be much better at managing ram and such, games close and open faster(sometimes run better too) although is you use something like KDE, you will see that it is slower than windows in the general operation of things. I use fluxbox for the speed and love it(gotta have some experience with the command line though). I love how the OS works, but windows is definatly useful. You can always try it, free downloads at
www.linux-iso.org. Popular distros are Mandrake, Red Hat, slackware, gentoo and debian. Mandrake is decidely easier than many others.
www.linuxquesions.org has a lot of information on the boards as well.