There's a wonderful metal box right near your house that protects your cd's from fire, earthquake, hurricane, riot, just about everything. It's maintained by the federal government. You don't have to pay any annual fee, just roughly 1 dollar each time you use it, on a pay-as-you-go basis. The box is called the mailbox. Just arrange with a friend in another state that you're going to send him a couple dvd's now and then so he can save them for you, in a box or empty 50-cd spindle with your name on it, and you'll do the same for him. Then you burn a disc once a month and send it to him and he sends his to you. Even if your whole town falls into a crevice (assuming you get out in one piece), hopefully he's far enough away that your data will still be ok. For ultra redundancy, do this with several friends who are widely dispersed.
You can also rent space in a local bank vault (safe deposit box) for 20-50 bucks a year. Those things are seriously fire protected.
See
http://taobackup.com for some more backup strategy in the form of Zen parables.