Carbonite
Well I've been using Carbonite for over 2 years now and with almost 100Gbs backed up online it can't be bad. Carbonite runs in the background all the time, so it is always backing up your data files. It's a don't worry type of backup, just install it and leave it.
If I find I need more processing speed or I here the hard drive working hard, then I can pause Carbonite for 24 hours, and it stops it's searching for changed files.
It's so simple and restoring files are as easy as coping your files from one drive to another, as Carbonite creates virtual drive of the backed up files.