Apple’s Time Machine is free, included in OS X, and easy to use for everyday backup and file restore tasks. You should definately use it! However, in a disaster recovery scenario there are more useful tools to consider such as Bombich Software’s Carbon Copy Cloner.
Carbon Copy Cloner can be used to create a Bootable Backup of your Mac and get you back to work quickly in the event of a hardware failure. A clone of your drive can enable to re-boot your Mac with the Option Key depressed (Think: “Holding down the Option Key at Startup gives you Startup Options”) and select your Hard Drive Clone as your Boot Drive. This can be done on your Mac if the problem was a hard drive failure, or on another Mac with similar specifications if your Mac failed to boot due to some other hardware related problem.
Consider employing a multifaceted backup strategy utilizing BOTH Time Machine and Carbon Copy Cloner. The price of an additional hard drive is insignificant when compared to the loss of even small amounts of data. What is your data worth? Restoring an entire hard drive from a Time Machine backup is possible but time consuming! What is your time worth?
You can setup Time Machine and Carbon Copy Cloner on a single drive, provided you partition the drive using Apple’s Disk Utility first. Alternatively, consider purchasing two backup drives… one for Time Machine and one for Carbon Copy Cloner. If you can afford it, get two drives. Even backup drives can fail!
Get Carbon Copy Cloner: http://bombich.com/