Mesch, I use Firewire since it is native to Mac, places lower load on main processor and has nice daisy chaining, but for compatibility reason USB might be better. I have three identical drives (two backups). One backup in storage at home and one at work. After adding/ripping 5 or more CDs I backup to one drive only (alternating them).
Carbon copy can make exact copy of the drive if they are of the same type but sometimes it just transfers files - I don't know why. It doesn't make any difference to me and is even faster. I've heard good things about SuperDuper.
