How about Lord of the Rings?
That's what first came to my mind too! Or another Tolkien book The Silmarillion. Both great reads and would make great discussion. We should probably clear it with the Hobbit Hole first - lol!
That is my all time favorite, long before it was made into a movie. The first time I read it I was 15 and listened to Pink Floyd's Dark Side of the Moon again and again as I read it. Even today, that music sends me back to Middle Earth. I never did get the hang of Elvish though.