I suggest a number of drive(s) in the User's Guide. Basically, I've tested and recommend (note -- ALL FIREWIRE, not USB, which cannot be used to start up a Power PC Mac):
- LaCie (2big is especially nice)
- Seagate FreeAgent
- Apricorn
- G-Drive
- OWC
- WiebeTech
- Maxtor OneTouch III