I am 99% sure you don't back up all of your files (ie all those documents, photos, videos, files and folders that are on your computer as we speak.)
Those who can't do, teach. I fess up to not being fully backed up myself. BORING. But seriously you need to do it, because if your machine crashes, you will be very, very upset. And stats show that 43% of people lose irreplaceable files every year.
So do one of the following:
1. Buy a Corsair Survivor Flash Drive and use it!
2. Use DropBox!
3. Check out my latest find Carbonite. What's cool about Carbonite? It installs a small application on your computer that works quietly in the background looking for new and changed files that need backing up. It looks and feels like it's part of your computer, and is integrated with your operating system (mac or pc)- there's no new interface for you to learn.
Of course, you can try it FOR FREE for 15 days. If you become a convert, it costs $54.95 a year - but here's another cool thing - there are no limits on backup storage capacity. Carbonite will back up all the supported files on your internal hard drive whether you have 1GB of documents (like me), or 10GB of music files (like my daughter who is personally floating iTunes.) And you can access your backed up stuff online, from any computer.
Wasn't Han Solo frozen in carbonite in Star Wars?