I've always loved having all of the books I've read on display. It leaves me with a sense of accomplishment. (Hey, I've got to take it where I can get it!) I especially think it's so cool in a few of the pictures below where they've color coded their collection and even how someone created a coffee table with books. It feels like books can sometimes be more of a pain to keep and to store but in this case you can use them as an interesting feature in the room vs a cluttered mess piled in the corner.