Bambi by Felix Salten is my go-to "favourite book" that I tell people. I read far too much to really have a favourite, though. But if I had to recommend one book I thought hardly anyone has read that I *know* is, like, universally good, I'd say Bambi. Obviously nothing like the movie.
Songs of a Dead Dreamer and Grimscribe - A collection of short cosmic horror stories by Thomas Ligotti
The complete fiction of H.P. Lovecraft
The Hannibal Lecter series - Red Dragon, The Silence of the Lambs, Hannibal, Hannibal Rising - by Thomas Harris
and Cloud Atlas. There aren't a lot of things which give me hope, but Cloud Atlas by David Mitchell is one of them.
Blindness by José Saramago, Island by Aldous Huxley, In Cold Blood by Truman Capote, 11/22/63 by Stephen King and Infinite Jest by David Foster Wallace. I am probably forgetting some, but these are 100% part of my being.
EDIT: Oh! The Bothers Karamázov by Dostoyevsky. How could I forget this one?