The Da Vinci Code
There's an interesting post here about Dan Brown's 'inepitude' when it comes to writing prose. I enjoyed the book greatly (have read it twice, listened to it on tape once), and yes, his wording is clunky and overblown and occasionally nonsensical, but Dan Brown managed to do two things successfully: a) he paced the novel and each chapter perfectly and b) he was able to throw together enough myth, history, art, and mystery together to build suspense. For me, that's the takeaway from "The Da Vinci Code" -- the awesome pacing and the perfect combination of ingredients necessary to create a riveting (albeit 'character poor') story.
And generally, I'm always going to come down on the side of a book that makes people read, no matter what its literary flaws may or may not be. I mean, even avid readers like me aren't rushing to the library to pick up James Joyce.