I have very little thread. DH made a small cabinet between two studs in my sewing room wall. He used two June Tailor spool racks and mounted those in the back in such a way I can remove them.
http://www.amazon.com/Mini-Mega-Rack.../dp/B000YZCSHE
There is a small glass door closing it all off. I think it is important to keep the thread in such a way to minimize the dust. It is also nice to see what you have.