For a few months now, I have been recommending Carbonite as my first choice for home backup.
I used to recommend Mozy.com. Mozy changed their pricing to a variable price depending on amount of data backed up, which I feel is confusing for people (“how much should I get?”).
Carbonite works fine and the price seems fair at $59 per computer per year. They offer a $229 for unlimited computers with a total of 250 GB. Carbonite will not backup external drives and virtual machines (pretend computers inside your real computer).
The gotcha with Carbonite seems to be with video files. If you do the trial, they do not backup videos by default. When you pay you have to tell them to back up your videos. If you do not you could have a problem when you go to restore after you have a hard drive crash and your video files are not up at Carbonite.
Here is the page at Carbonite that explains this:
http://carbonite.custhelp.com/app/answers/detail/a_id/1336/partner/carbonite
Music and Video Files
While in your free trial period, Carbonite will not automatically add your audio and video files to your backup. Once you purchase a subscription the music files will then be added to your backup (as long as the folder was originally selected for backup). This is because these files tend to be larger and can lengthen how long it takes to complete your initial backup, resulting in not being able to test the product effectively.
Adding a music or video file to your backup is as simple as right-clicking and selecting Carbonite; Back this up. (On a Mac you can use the Carbonite Preference pane to add files.)
It is important that you follow the directions or else you might get an unpleasant surprise.
What if you have an external hard drive you want to back up? Try backblaze.com
Whatever you choose make sure that you do a backup, the consequences of not backing up can be expensive and/or frustrating.