I've got some external hard drives that I rotate in and store off-site but still nearby (down the street) for some data. I also have constant online backups running to various locations/services (Linode, AWS, CrashPlan, Dreamhost, some private services). I don't backup everything, only the irreplacable personal data (so, I'm not backing up Wikipedia dumps); at current count, at most 6TiB of the data is irreplacable. I also prioritize, so even out of that data, the absolute most important data is backed up more often, to more locations, and the less important data is backed up to fewer locations.
Cool, thanks! That's pretty close to my current approach as well. The super important data is replicated into Dropbox, and a few hundred gigs of somewhat important data is cloned over to a friend's box manually every few weeks.
