I have a basic understanding of each one but was wondering if I could get some input on which is best for me.

Currently I have in my system a 128 gig Crucial m4 as my boot drive and a 1.5T Western Digital as a collection drive. Pretty much everything on this collection drive I would like to keep and have a functioning backup of.

At one time I had an external drive that held my FLAC collection. This drive died, I had no backup and have since used the Zune service in the meantime. The thought of re-ripping an tagging my files has seemed like too much of a chore until now. I'd like to do this again and have the files available when my PC is off so I can stream them to my Oppo BDP-93.

This point makes me think the only options then are an external drive or NAS. Problem is with 1 external drive there is no backup. NAS seems like it's very similar to having more than one external drive with the benefit of having it wired into your router but also seems to be the most expensive.

I'm thinking of having about 3T of storage for the time being. I guess I could get by with having the computer on during streaming if necessary and if the cost is significantly lower. Basically I'm looking for ease of use, lots of storage and the lowest price possible. I'm also going to have more than music on this drive. I will be putting sensitive documents as well and scanning most of my personal paperwork I have on hand.

Ideas?