Mine has always been "The Lord of the Rings Trilogy." I think J.R Tolkien is the god of everything science fiction, and probably the best author to come out of the "Great Generation." What do you like friends?
LOTR is a great epic. There are way too many good books out there to try and narrow it down to a solitary book in a single genre (for me!). I suppose the one I read more than any other is Pride & Prejudice, but I'm not even sure if it is my absolute favorite. But, it certainly is the most dog-eared in my home library.....so, I'll go with that one.