1. High-end DVD burner, burn onto 2 (master and back-up) highest quality DVDs, test both after burning, keep in separate locations.
Study the different standards for burners and media for interoperability issues.
2. Transfer onto a high end high capacity deluxe-edition (250GB+) hard-drive for triple storage/ultimate protection.
Study the technology behind hard drive design, and make sure you get a 48bit addressing drive that gets past the "137 gigabyte barrier".
3. Keep yourself current on issues relating to "file migration" (when current TIFFs etc become obsolete), and when needed convert old (lossless) file types into the new (lossless) file types.
Barring the gross physical destruction of your media (which includes improper storage and handling), these rules should keep you good for the next (ten + ?) years easy.
Oh, I almost forgot the most important thing.
The more ruthless you are editing and discarding images you really shouldn't keep, the less time and money you spend doing all of the above.