Reformatting? I bought a whole new drive for it (one of the WD 120GB drives with the 8MB cache) about a month ago, installed it and put a minimal OS X 10.1.5 setup (OS, mail, browser, not much else) on it, and basically just waited for Jaguar.
Saved all the trouble of reinstalling everything twice. I've got it split into a 70MB main partition and a 50MB workspace/scratch disk.
So now I've got the 100MB/8MB WD that used to be in the machine in a Granite FireVue Firewire enclosure and dedicated entirely to iTunes, the old 100MB/2MB WD that was a secondary drive in the machine in an older Firewire enclosure and partitioned purely to provide "clean" boot installs of OS 9 and OS X (as well as backup partitions for my wife and myself), and the 80GB Seagate that actually came in the machine sitting idle (since it really didn't like being in a Firewire enclosure for some reason). It'll probably end up in my Linux everthing-server box if I can establish whether the BIOS'll recognize a drive that large.