I saw this SD Card from Kodak:
at the checkout display at Wal*Mart. The packaging claims the card will last “up to 50 years”.
They’re cheap enough that this might be better for the amateur photographer than trying to store his data on a crash-prone non-RAID’ed, non-backed-up hard drive.
On the other hand I can’t get, for my current computer, a reader or drivers for the memory card from the digital camera I had 11 years ago – it took an industry-standard AIMS Type I flash card (pre-ATA standard). Will we be able to find an SD reader in 50 years? Maybe at a specialty shop, if you’re really lucky.