Only 50Gb each at the moment though that is currently enough for the stuff that I really care about (but I need to think about upgrading soon): the mail and web servers that I run for me and family+friends (two weekly snapshots and two daily, managed using rsync and cp -al so it doesn't take nearly the space of four full copies), source controlled source, general documents (again using snapshots to keep multiple instances, though I'm considering moving my docs into source control for keeping a history instead), configuration files for all my servers and such, and so forth.

There is a chunk of stuff that I don't backup off-site in this way but do backup offline at home (photos and MP3s for instance) and a large chunk of stuff that I don't backup at all (large media files that I could re-obtain from elsewhere as easily as I could draw back down from an offsite backup, should the RAID array fail in a way it can't survive or I cock up and accidentally delete stuff).