Glad I'm known for my extreme backing up views. I wouldn't trust a drive like that on, Josh--I've had drives from everyone shit out on me. Maybe you could use it as "storage for stuff I don't care too much about" or something.
I now recommend a three-pronged backup strategy, since you can't use Time Machine to back up network attached storage drives (only *to* said drives).
1) Time Machine or equivalent for local files
2) Dropbox for your "documents" if you are a writer of any kind. If you work from a laptop this ensures your shit is backed up from anywhere you have a network connection. (My Dropbox syncs from my work laptop to my home computer and the Dropbox folder is also backed up through Time Machine)
3) For NAS, I use rsync from a command line. This is a bit techy, and I'm sure there's a way to automate this, but I don't because I also physically unattach my drives from my Airport Extreme (where they're made available, read-only, to things such as the tiny PC running XBMC that attaches to my living room TV) and attach them to a regular computer. This is because running backup over a network is dicey, maybe not if you have a gigabit ethernet connection or something. Anyway, rsync is the best; a quick "sudo rsync -a --delete /Volumes/music/ /Volumes/backup" from the terminal is the most efficient way to mirror a media collection computerly possible. The point is, make sure that you run backups even of drives that Time Machine might not capture.