I've been using epitome for about a year now for deduplicated backups of my personal data . It has a tar like interface so it's quite comfortable for a unix user and setup is a breeze, at least, on OpenBSD. You can easily cron it to backup your directories on a daily basis, and it takes care of the deduplication of your data. You basically are left with a meta-file that you can use to restore your snapshot at a later date. As I said the interface is tar-like so doing a backup is as easy as:
# epitomize -cvRf 2010-08-16-home.md /home
Note that epitome is abandoned, only partial copy of website at https://web.archive.org/web/20140908075740/https://www.peereboom.us/epitome/ remains.