I too have a large stash. My problem is that organizing it never lasts past my next project (sigh). I have it organized by color -- because of the shelves I have need to lay the fabric flat so when I want to get to a piece I have to unload from the top down. It ususally takes me longer to get the fabric (and select the fabric) for a project than it does to make the project. I am trying to force myself to make scrappy quilts since I have wonderful scraps that I don't want to toss.
We are retired and I try not to buy new fabric -- DH gives me a gift cert to my favorite LQS and I try to limit my purchases to that and I only shop sales. DD and DDIL both "shop" my stash on occasion (wish they did it more) so they don't have to buy much fabric for their projects. I donate fabric to church since we make charity quilts with it -- I hope to be able to reduce the stash a bit more soon.
Great topic -- makes us think about what we have.