Sign up for cloud backup service.
Make sure it’s saving all the files it needs. By default Mozy omits some files (source code and executables might get skipped).
Get cloud sync for your “work folders”. Store your current projects there.
You can use Dropbox to roll your files back to earlier state when you mess up. It’s layman’s version control.
If you can’t or won’t use cloud, use a good file sync program to create backups:
Remember to take media off-site or sync to a remote computer at a different location.