1984 by George Orwell. I finished this book two nights ago. It's been on my reading list since highschool and I can finally cross it off! It is such a powerful and depressing story. I don't know that I would have fully appreciated it in highschool.
"Catcher in the Rye" When I first read this book, I really didn't like it. But when I went back over it in my mind I realised how utterly brilliant it is.