Decorating with Books

I love books.... I wish I had a chance to read more than I do.  I have, what seems like an endless list of books I want to read.  I also love to decorate with books.  Last night, I was visiting with a girlfriend at her home for the first time and I was struck with total envy - a room where every wall was a bookshelf.  Hopefully, someday, I too will have a room like this.  Until then, I can just drool over hers. Do you have a lot of books?  Wondering where to put them all?  Here are some great ideas!