I am also thinking about a backup stratagy for my home network, but am concerned about a rsync-only stratagy. If my house burns down, it will take the rsync disk with it.
I have a cheap computer in my unattached garage that I have a cat5 wire ran to. So basically I do offsite backups. Another alternative is to put a machine at a friends house. Do an rsync on your local lan to get the bulk of the data backed up to the machine, and then lug it over and hook it up to their internet and port forward port 22. Then you can use rsync with ssh via the internet for your backups. I do this with some small business clients. -- -=/>Thom