annie/georgia,
I have a 1 TerraByte USB hard drive (mine is a Western Digital)...
that is always attached to my desktop, and I have a backup scheduled for "My Documents" and other folders on a weekly basis...
(scheduled backup software was included with the ext. HD, and you can customize the folders you want to backup)...
and I have also picked the option to keep 20 weeks of backups...
It cost less than $100 for the ext.rive and I have all my stuff backed up, every week, all the time...
well worth the price... I know, as I have lost Hard Drives more than any other hardware problem...
I also have the drive networked at home, so it backs up My Desktop, My laptop, Deb's laptop, the Desktop in our Guest Bedroom, My Netbook, and the laptop in our family room...
also Mine & Deb's old laptops whenever they come online...
with all those PC's I have only used about 1/3 of the external drive's 1 TB capacity...
that includes the 40,000 plus pictures we have... (OK, theres a LOT of duplicates in the picture category and most are high definition!)
I also replicate/merge all of our "My Documents" folders between all our online PC's weekly...
The replications/backups take place at 3AM every Wedneday...
replications first, then when finished, the backups...

what I'm doing is way overkill... but I don't ever lose anything... and it's done automatically... so I never have to worry about it...