Awesome, cheesyking, that works great! I examined my /etc/fstab's existing lines before posting, but saw stuff about UUID=blah in there, and figured I'd better check around before doing anything rash.
The drive is indeed a hard drive (120gb 2.5" sata laptop drive). But I figured, since the server is a laptop, and both it AND the USB drive are powered from my UPS, that journaling would be pointless. Should I reconsider?
the UUIDs are actually a much better way of doing this as it's possible the order of your drives might change (say if you left a usb flash disk plugged in at reboot or added another internal disk etc). Google finds lots of info doing it this way but here's a very brief intro:
use the blkid command to find the UUIDs on your system...
Then just alter the line in fstab to use the UUID like the other lines that the installer created. NB blkid prints UUID="xyz" but fstab uses UUID=xyz without the "" so be careful when copy and pasting!
And yes I'd always use ext3 over ext2 UPS or not, unless there's a very good reason not to (like you're using a flash disk which the journalling will prematurely age)
NB lots of pages on the net (and even the comments in fstab on my ubuntu 9.10, which is actually an upgraded 9.04) talk about using the vol_id command. This command doesn't actually exist in 9.10 so don't be surprised if it doesn't work!