Would recommend two hard drives and Powerquest Drive Image. I back up about once a month for the whole drive. I keep all my files on a seperate partition and copy that across to the other drive frequently, with a copy of my Outlook.pst. I've also keep that lot copied onto CDRW regularly and I've also got a hard copy of my drive on CDR. After a major crash it would take 30-40 mins of copying to be back where I was.
Sounds like overkill, but once you've lost everything the term 'never again' springs to mind. I lost mine about 18months ago - the usual stuff like all my walls, skins etc, plus a huge movie collection, gigs of astro photos, about 250 UT maps etc...
The only thing you can rely on with a hard drive is failure, it's not 'if' but 'when'. Hope you get everything back soon.