Greed - Staring at your bookshelf and STILL wanting more books to pile on that thing. Who cares if it's sagging over! MORE BOOKS.
Sloth - Forget about life, I've got a book. I think I'd rather lay in bed reading than write that history paper.
Gluttony - Um, I don't know about you but I LOVE to snack while I read. Namely, chocolate.
Pride - Staring at your beautiful bookshelves and wondering how you got so lucky.
Wrath - When publishers reject your heartfelt book request for that one book you want so desperately!
Envy - This has got to be the easiest. Can you say you haven't ever been a teensy bit jealous at the sight of other bloggers piles of books that you don't have?