As I use multiple Macs in many locations, both portables and desktops, my main concern is the availability of the data when and where I need it, as opposed to simply backing up data. I rely upon Synchronize Pro to keep all of my machines current (http://www.qdea.com/synchronize_pro_x_intro.html). In addition, my main machine is backed up automatically using Apple's Time Machine utility.
David Kerwood
U.S. Naval Sea Cadets of Rhode Island, Inc.