The Hitchhiker’s Guide… is probably my fav, but it’s more of a cult thing, so I just couldn’t in good conscience name it as the “greatest book of all time”.
I guess the greatest novel I’ve ever read would be Crime and Punishment.
The Best (IMHO): “All the King’s Men” - Robert Penn Warren
My Favorite: “Watership Down” - Richard Adamsl
I would be inclined to say that Lord of the Rings is the best English-language fiction book in history, but I don’t know about best overall. I’m inclined to think that it’s probably either the Bible (or one of the translations of it) or the Q’uran.
And no, I’m not considering the Bible to be fiction. It might be fictionalized, but Jesus was, at least, a real human being.
LoTR
Catcher in the Rye
1984
Hamlet/Macbeth and Othello, terrfic plays still relevent in are ‘modern, educated socities’ - shame really. However these are ‘plays’ not books, and there IS a distinct difference so they dont really fit into this thread.
What a great come back line!! I wish I would have thought of it. I could not quit chuckling.
Greatest book of all time? An impossible task. Too many.
However some quick choices:
Historical/Biography: ** Founding Brothers and American Sphinx: Character of Thomas Jefferson** both by Joseph Ellis
Classical Fiction: Any of Thomas Hardy’s novels with special emphasis on…The Mayor of Casterbridge and Return of the Native
Modern Fiction: Margaret Atwood’s ** Alias Grace; Robber Bride; Cat’s Eye; The Handmaid’s Tale**
Essays: Gore Vidal’s United States: Essays 1952-1992
Other: Dava Sobel’s Longitude and Galileo’s Daughter
Many great books have been mentioned here…
But you know, there are 2 books that I have read over and over for years.
The Princess Bride - S. Morgenstern (Better than the Movie - only because it lasts longer.)
The Stand - Stephen King
yep, pretty sad, but I read them every year.
(My vote for best edition of the Bible is The Amplified Bible)
Isn’t kind of inherently impossible to say what is the “best” book?
There are too many different criteria. You have to state either your favorite, or what choice makes you look the smartest. 
Most "influential: Bible, or Koran ? Gutenberg Bible? Epic of Gilgamesh? Beowulf? Don Quixote? Ivanhoe? Tom Jones?
Favorite? Hitchhikers Guide, no doubt.
And another:
Bored of the Rings!
“Pepsi thought he saw a Rider, but he had been into the pipeweed earlier and wasn’t sure…”
Definitely the best parody ever.
I have always liked The Caine Mutiny by Herman Wouk.
-Bubba.
What a great come back line!! I wish I would have thought of it. I could not quit chuckling. 
im sorry you think the bible is fictional. *1984 = another great book, The Return of the Native = not great and very soap-operaish book. and i think shakespeare (i cant spell) was a perverted person who had a very skewed outlook on life.