I think Target Disk Mode is one of the better kept secrets. I use EMC/Dantz Retrospect to backup my various computers. The server is a PowerMac G4. To backup my iBooks, I just boot them into Target Disk Mode and hook them up. The backups are much faster than across the network, and more compete because there is not operating system running from the disk that you are trying to backup. And you don’t need a client license, since you are backing up a “local” disk.
