If you haven't taken to the new Backup software in Windows Vista and want something more traditional where you can actually choose the specific files and folders you want to backup then this piece of software is perfect ... and free
AceBackup: The free Backup Software
I especially like the backup approach where it copies (compresses and encrypts) the files you want backed up and can be set to only refresh the files in the backup that have changed.
Edit - 10th June, 2008 - started having a few problems with this program. For some reason it started to ignore files and give some strange errors. I think things got corrupted. I now use Cobian Backup 9.