JWZ as usual offers good, if acerbic, advice; today on backups:
I am here to tell you about backups. It’s very simple.
Option 1: Learn not to care about your data. Don't save any old email, use a film camera, and only listen to physical CDs and not MP3s. If you have no posessions, you have nothing to lose.
Put one of these drives in its enclosure on your desk. Name it something clever like "Backup". If you are using a Mac, the command you use to back up is this:
sudo rsync -vaxE --delete --ignore-errors / /Volumes/Backup/
If you're using Linux, it's something a lot like that. If you're using Windows, go fuck yourself.
NB: There are ways to do this in Windows, too. Not as simply, mind you, but it can work.