The key is always having multiple backups. Different media is also a key. But remember dvds and cds also have limits too.
I'm in the process of digitizing 12 years of sound super 8 film. My first 2 hours from the vendor are outstanding (1975-1986). I will then be putting it on the disk drive for easy access but will have dvds, minidv tape, and the original film as my masters.
I have the same set up with my digital photos. CDs and disk drive for access.