Watching an episode of a PBS series called the Great American Read and I don't really have a favorite over all them there a probably favorites in different categories.

Best Sci-fi series would be Foundation by Asimov.
Best Sci-fi comedy would be Hitchhikers guide to the Galaxy.
Best stand alone Sci-fi book would I, Jedi.
Best non fiction would be Demon Haunted World: Science As A Candle In The Dark.

What your favorites?