Advice on NAS

I tried setting up a second computer as being a quasi server, a location to hold some larger hard drives so that I could store the files I was not working on in an out-of-the-way place.

Fail. Really impracticable.

So, I have 6 hard drives ranging in size from 1tb to 500gb. What I want is remote storage so I can keep my work area organized and still have relative easy access to retrieve files if I want to work on them. I do not envision working on the files directly from the remote location, but bringing a copy of the file to my work area.

I have been looking at NAS systems. What questions do I need to ask? What do I need to look for? What are others' pieces of advice?