It's no longer just enough to keep a second DVD in a safe place. Often, in addition to multiple DVD copies of files, I strongly suggest to my brides and grooms to keep copies of their files both on an external hard drive and on a separate place online (like shutterfly or kodak.com).
I like the idea of looking at your images on every anniversary as the files are once again archived. Maybe there will even be a warm and fuzzy thought about your photographer in there as well!
