The verbatim armoured life time warranty ones should be better than hdd's prone to surge or electrical/mechanical failure. Make two coppies if it helps and keep them seperate. There was a Iomega Rev drive with 30gb cartridges, basicaly a super sized version of the zip disk. But like its predecessors it is not so popular.
http://www.zdnet.com.au/reviews/hard...9150058,00.htm
But the problem with fast rewritable solutions is people tend use them as external storage rather than backup archive storage. With a DVD you write once and add more DVD's to the set as time progreses, you may also reburn some older DVD's if you overly protective.
Regards