For September, Dreamhost has announced a "double disk space" sale - for all new and existing accounts, the starting disk space has been doubled. Even better, the weekly disk space increases have also been doubled. Since I have a Level 1 account (which previously started at 2400 MB of space), I now have almost 5 GBs of space on the Dreamhost server (4800 + 80 MB from weekly increases). This amount will increase by 40 MB weekly.
Since I am barely using 2% of this space, it is feasible for me to use Dreamhost as offsite backup. I am considering creating an application that would collect data on my computer that I want to backup, compress it with Gzip or something similar, encrypt it with my GPG key (to protect it from prying eyes), and then use SFTP to transfer it to Dreamhost.