An hour ago, I lost my entire Ubuntu installation to some unknown factor. Thankfully, I have backups of all my pictures (Over 6 gigs worth!) and my software projects. But I don't have all my videos, music (though most were copied from my iPod so it shouldn't be too hard to replace), and all my applications that I had downloaded to it. What's even worse is the fact that I lost my installation CD. So now I have to wait for Cannonical to send me another copy. Yeah, I could download it, but I have a download quota and no good download manager.

Moral of the story: MAKE BACKUPS!!! Plenty and plenty of backups. And don't lose important installation CDs.