Archival uses for blu-ray and hd-dvd

The first blu-ray and hd-dvd burners are coming to market and the initial reviews reel off every spec except the one I’m most interested in: how long will these discs last? AFAIK current recordable dvd’s can degrade in as little as 2 to 5 years. Does anyone know if the next gen media lasts any longer?

I also posted this question on the forum: