If you are getting a feeling that you own enough fabric, you might want to join a Yahoo group called "stashbusters". They are an inspiration to me -- and I have would most would consider a smaller stash -- working in a fabric store, I have a constant supply so need not to buy it today. That said, I have found that in the last couple of years as fabric prices have risen, I've been buying more when there were big sales! So now have enough so that just a few days ago, needing to make a store sample for an upcoming class I'm going to teach, was able to construct a nicely coordinated 48" square quilt from .... ta da .... my stash! That felt wonderful!
Do I still buy -- you betcha! But more apt to see what I have at home first and add to those wonderful pieces which I already know I love. Give them the chance to see their destiny in a quilt. I enjoy going through the selection process - and having it organized is a wonderful way to make sure you didn't miss some wonderful choices.