I have a mac mini running OS X server. There is a WD MyBook USB 3 3 Tb drive connected to the server as my data drive. This drive is shared across the network. It stores all my Photos, music, documents, movies, etc. The drive is backed up every night to another WD MyBook USB 3 3 Tb drive, using super duper. The main drive is also backed vis crash plan. It's this for a larger drive which will most likely be a WD MyBook USB 3 4 Tb drive and I will buy a second to have a daily backup. This to me is the most cost effective route I can do this for about $250. I am pretty happy with the performance of the drives. I think with large copies to the attached clients the bottleneck is the network speed, also this is my home network so it's a leisurely environment. However I am looking for suggestions for alternative before I do the upgrade. Any ideas?