I'm the worse. Books are a complete addiction for me. I even speak of them in drug terms - using words like "fix." I spend tons of money on books yearly. I often buy site unseen (which wastes a lot of money), I'll buy from my favorite authors without reading first, I'll buy based on recommendations, etc.
I stopped tracking how much money I spend because it would be depressing. I can say I don't have any other really bad habits so that keeps me out the poor house. I'm not a clothes shopper or purses, etc. Just books. Lots and lots of books. Maybe too many books? Nah, you can never be too well read or own too many books.