I'd like to buy a portable external hard drive from which to run various applications...so I've been looking at firewire connected drives, because of their higher speeds...I'm wondering, though, if this is overkill...would a USB 2.0 drive be sufficient? I've got a 1.2 Ghz G4 iBook...Any recommendations as to which one I should get? At present I'm considering Buslink's Disk-on-the-go...I can't tell, though, if it is mac-compatible...