I've been using Linux for a few years now, specifically Ubuntu, a few other Debian distros, and CrunchBang most recently. People often ask me why I'd use Linux, and while I could list off all the obvious reasons that everyone gives, here's my list:
1- Having Linux installed on my computer confuses people who try to use it. I like that look of panic and confusion that spreads over their face when I log them in to let them check their Gmail. CrunchBang does an especially good job at confusing new users. I love it.
2- I can take the money I was going to spend on Windows and buy 16 gigs of RAM. And have enough left to order pizza.
3- It doesn't run all the software from Windows. This is great, since I have a watertight excuse whenever I don't want a particular app installed on my computer by someone else. "What do you mean it can't run Dora's Happy Playground Barftime? Fine, I'll go ask Mom if I can use her computer."
4- My computer boots faster than your computer. (If yours is running Windows, that is.)
5- I can plug in as many keyboards as I have ports for, and they'll all work, at the same time. This further enhances the confusion factor for foreign users.
6- When I install my OS on a fresh hard drive, I never have to patch my computer up to the newest version or hunt for drivers after the install. The installer does it for me.
7- Full drive encryption RIGHT OUT OF THE BOX. Booyah!