If you have a network of computers, you can of course just copy files between them and hope that they all don’t crash simultaneously.  This requires some setup, but is an inexpensive approach.

Alternately, if you are willing to invest $175 you can buy an external hard disk which will make a nightly backup copy of the contents of your primary hard disk.

The upside of this approach is that it requires no user interaction (it is total automated).  It also backs up the contents of your entire hard disk, so you won’t accidentally miss an unforeseen critical file.  The other upside is that it backs up your operating system and program configuration.  Restoration from this format is much quicker than manually reinstalling your operating system and program files.

Norton Ghost offers a good external backup system:

• Norton: http://us.norton.com/ghost