I would like to just point out a few things.
1. Do not get an LG optical drive just because they rip slower to try to be more quiet when BD/DVD/CD's are used. Data discs would be fast.
2. Storing all files over the network should not be an issue(Having a backup plan just like with any system is a good idea, RAID will not recover data from a virus or accidental deletion), but please ensure you either have a setup for recovering deleted files(as Windows does not send network files to the recycle bin) OR tell windows you want your documents folder to be a mapped network drive(in my testing, "Users" folders will actually get a recycle bin on the local machine[I think it is still on the networked drive, but the server will not see them in its recycle bin.].).
Please note that a few programs or games may have some issues with moved users folders. I have used symbolic links to get around this(you have to do it in the right order or Windows will give you an error. If you need help with this, PM me
), but you will loose the recycle option again, so be careful when deleting files.
A solution maybe to try something like FREENAS as opposed to Windows for your NAS system as this will allow you to setup a recycle bin on the server(Wish I used it, but my media center[runs Windows] is my "NAS").
You may also have to play with security settings for the network shares to work right. Strangely enough, Elevated programs may NOT see shares unless you run the "net use" command from an elevated command prompt first(once per reboot, so making a .bat or .cmd file to do it faster is a good idea.).
Sorry this is not much about the system, just some things for NAS use.