So I thought I'd tell y'all what we're using for back-up now. Kevin bought us a OWC Neptune hard drive (which comes with the Retrospect backup program). I asked him last night how much it cost, and he didn't quite remember, but thinks it was about only a dollar/gig, so he went ahead and bought a biggish one -- $250 for 250 G. Which should last us a good long time, since he has an 80 G hard drive, and my little baby is only a 20 G. It took a few hours to make the first full backup (which he handled and I utterly ignored), but last night he showed me how to do nightly backups on my own. Plug in firewire cable, turn on machine, tell Retrospect to run, click Backup. Don't eject/shut down while backup is running. That's it -- pretty straightforward. The backup took about ten minutes, but since it's all automated (it's only backing up the files that changed, which is mighty clever of it, I have to say), I can just walk away and come back when it's over.
I don't honestly expect that I'll back up every single night, but I think I can get onto a weekly schedule without too much hardship. And the plan is in the next few days to make a second full backup, and then alternate between them, so that if one gets messed up somehow, I still have a week-old one that's good.
I'm not entirely sure where Kev bought this hard drive (actually, I have no idea, other than it was someplace online) but if anyone's interested, let me know and I'll ask.