I've been burned before, so now I use a mix of incremental networked backups and offsite storage. My home server runs ZFS, snapshotting every hour/day/week. Critical files get sent off to TarSnap each night. Friday nights, a script archives important data to a set of tar.gz files that are written out to an external HDD. Saturday mornings, I take the HDD to the bank and swap it with its counterpart in my safe deposit box. It's a bit cumbersome, but it works for me.