I'm gonna have to be terrible boring here and say the LOTR books and the Harry Potter books (I'm at the moment up to book 5 of HP and then it's time for The Hobbit, Silmarillion and the trilogy *s*), but mostly because I have them on audiobook (which makes it much easier for me to focus, then to read them...) :) but also because they are my comfort books and because they make me happy ^.^ and I def. think I will have to listen to Hitchhikers guide again, I so love those books :)