I keep a rolling backup that is now up to about 20GB (mostly music, some videos, a lot of school and work projects). The latest home for this archive is a 1TB external hard drive. The downside to this is the possibility of theft - whenever I throw out a drive, I have to check to see if it has an archive and delete or destroy it. However, this is an manual process and I sometimes go 6 months or more without updating it.
I suppose I get away with this because I am a programmer and most of what I do is automatically backed up elsewhere, be it gmail archive, source control etc.
