I use a NAS box running RAID 1 (mirroring) for all my stuff, basically with mirroring if 1 HDD fails you have an exact copy on the other drive. As long as you swap the failed HDD with a new one before the other drive fails they'll sync up so you have 2 copies again. I also run a media server on the box so I can stream music without needing to have a PC turned on and can login to it from my mobile to get it to download music I hear about while on the move.