Photography is my hobby, so I have a lot of files to back up. I recently upgraded to SyncBackSE and find it easy to use and it does incremental back ups.
As a second backup, I just started using Carbonite, which also makes automatic backups. For the cost, it's better than having to have an external drive kept in a bank safe deposit box or elsewhere. Most of us don't think of the fact that even if we have external drive(s) for backups, if they are in the same location with our computer, if a major tragedy occurs, the external drives may be lost as well as our computer.