Originally Posted by MTI

Backing up long term storage items like photos, video and documents that aren't frequently edited should do well on optical disc (CD, DVD, BluRay) or solid state devices (thumb drive, SD cards, SSD external drive) for as long as the hardware is there to support it.

Backing up the more frequently updated items, like e-mail, system registry, desktop settings, business ledgers, are probably better suited to be backed up by an automated system on a scheduled basis, and preferably on a system that can take that backup image and dailies and install a complete backup onto a new hard drive.

If there's critical data anywhere on your machine, having it offsite on a usb thumb drive can be very smart. Critical data can also be great to have on a "cloud" server.

Currently I use all three systems. I have long time archived files on DVD and USB copes of the DVDs are in a safe deposti box; I use Time Capsule onto an Apple Time Machine to do the daily backups of all the home network computers and finally; Apple's Mobile Me provides "cloud" storage for e-mail and important files.