Computers are quirky. You just never know when something is going to go wrong with them. You want to make sure that you have multiple copies of your data. Imagine how devastated you'd be to lose your family database or all the scanned photos that a distant cousin emailed to you.
I’ve been using Mozy to save my files. It’s a service that you download a small program and it will automatically backup your changed files as often as you specify. The original backup does take quite a while, but once that’s done, it’s pretty fast to update your backup.
The largest benefit to this is that it’s an off-site backup. If your house burned down, having 100 backups won’t do you any good if you kept them in your house.
You can get a free account to backup 2GB of data. Use my referral link (or type my referral code 4YXZQ1) and we’ll both get another 256MB of free space. For each friend you refer after that who downloads and backs up their data once, you’ll get an extra 256MB.
Why not give it a try? You’ve got nothing to lose and a lot to save!