One of my drives no longer shows up on my desktop. I think it's failed. I was talking to a guy today who knows Macs, and ghe suggested that I switch over to Firewire drives. He gave me info on this site
I have been editing M100 on single (i.e. - not Raided) 120-gig Firewire drives using just the Firewire port on a G4 for several years. My drives have 8mb cache, and they easily sustain 225-250kb throughput. Using 8.2.1 caused no problems with this workflow.
External RAID enclosures from Sonnet and Firmtek that allow hot-swapping drives provide an economical option in the long run.
I'm using the Firmtek 2-drive card and enclosure and they're working nicely. Sonnnet's solution was just announced and their enclosure has 4 bays instead of Firmtek's 2, and it also has an internal power supply instead of an external one. Slightly cleaner installation... no brick.
Hitachi 250-gig drives are about $140 each plus another $20 for a "sled". At about $160 for 250 gigabytes of fast storage, it's not a bad deal.