I had this same inventory control problem with cookbooks. I solved it by making a rule for myself: No new cookbooks until I cook 30% of the recipes in all the ones I already have.
I have this same inventory control problem with computer science books. Good textbooks are expensive. If you implement a utilization rule like this, you can save yourself a lot of money on books you never end up reading. B&N, Borders and their ilk have liberal return policies, as does Amazon. This will help save lots of money. Also, the utilization rule prevents you from disadvantageous conditioning. The retail pleasure of acquisition can drive you to buy books faster than your actual reading rate.
I have quite the stack of books on my "to read" list, but I keep working my way through them (and adding more to the pile.) So it goes.
I have the same phenomenon with Irish Trad tunes I want to learn. The list is ever growing. (There are at least 30,000 of those.) My solution? I only learn the tunes I fall in love with. Life is short, so why waste time with something that's just "nice?" I think I'm going to apply this to books and other contexts.