I haven't read The God Delusion yet, but have been meaning to.
Of all Dan Brown's books, I liked Deception Point the most. However, they are far-fetched, but hugely entertaining. I'm looking forward to reading his latest offering.
Would have to be Dune and the rest of the series. It was ahead of it's time such as comments on politics and ecological issues but a great sci-fi book.
i'm not sure i have a favorite book but i keep re-reading LOTR, and terry pratchett discworld series (mort and weird sisters esp) the sparhawk series by david eddings and i love tom saywer and huck finn books