Backblaze is one of the easiest unlimited online backup services around, continuously backing up all your important data in the background without bogging down your system. For today only, you can get a whole year of BackBlaze for just $US25 if you sign up through AppSumo.
Normally, Backblaze's service is $US5 a month or $US50 if you pay for the year, so this is a pretty sweet deal. It's for new customers only and covers just one computer, but you can buy more than one if you would like to back up multiple computers (Mac and PC).
Besides being fast and simple, Backblaze can back up external drives, and the service can send a flash or USB hard drive to restore your files if you need it. Oh, and if you don't like the service, there's a money-back guarantee.
Don't ever worry about los8ing your precious files [AppSumo via CNET]