I may be the minority but I don't see the need for a RAID. On my NAS I have about 300gb of music, which I backup to a USB disk. Since the files don't change often a disk crash would just entail buying a new drive and restoring from my backup. I do not yet have an off site backup, but am working on it. I will probably buy another HD and store it at the office, maybe using the PogoPlug <http://www.pogoplugged.com/>. And I still have the original CDs in the basement.

Main system (when room is done): 861v4, 7 x DSP33, SW1600, Oppo, Sonos