I'm not really interested in buying anything else. It just bugs me to have it sitting there doing nothing. I figured it might be fun to torture myself with learning a thing or two about linux. Besides, what's a better prize than playing a game of asteroids? I'll get something going...
Fedora or Linspire are the two distros that are considered the most newb-friendly. Start with either one of those and you have to jump through hoops to do anything powerful.
If you're looking to jump neck-deep in linux, go for slackware or debian. Waste-deep, go for Gentoo. Knee-deep, go for a knoppix distro or SuSE. Finally, if toe-deep is what you're after to test the waters go for Fedora or Linspire or maybe Mandrake.
Generally speaking the easier the distro is to navigate and get used to, the more system resource it will gobble up. The more gui-friendly are the ones that a lot of people find easy to use, but are also the resource hogs. Once you learn linux and aren't afraid of compiling your own kernel and X.org distro, you'll be golden

Head on over to
DistroWatch, click the "Major Distributions" link on the top-right and read the descriptions of most of the major players.
Good Luck. Welcome to Linux, and enjoy your stay!
-Steve