Facebook had another top 5 thing going on and I saw that one of our other fretters had answered it. So I did too. These are the ones I listed off the top of my head.

The Lord of the Rings, Tolkien
To Kill a Mockingbird, Lee
One Flew Over the Cuckoo's Nest, Kesey
The Martian Chronicles, Bradbury, and
The Adventures of Huckleberry Finn, Twain/Clemens

I am enjoying the Dark Tower series, but I am not ready to say it supplants one of the above yet. What are your five?