Looks like David Pogue got himself a TV show and one of the topics discussed was transferring content from dying formats like VHS to longevity-unproven formats like DVD. Essentially, Pogue finds out that commercial transferring services are pretty terrible (they usually don't color correct) and the only way to accurately transfer stuff from actual movie reels is to pay an arm and a leg to NASA scientists (or just about). He does bring up a good point about storing our priceless content an any of the formats du jour.
How long will DVDs last? Nobody really knows, that's why archiving our precious moments on them might be foolish in the long run. Also, since formats change all the time (storing data on punch cards wasn't all that long ago), it may be silly to try to think that once your movies are on DVD, they're good forever. The moral of the story? You're screwed.
Saving Home Movies From Disappearing Formats [New York Times Blog]