Oz and Ends had a nice little discussion going on The Idea That the Story Is True versus, say, it's really being true. It's kind of a mind-boggling concept.
The article J.L. Bell links to includes the following quote: "Mezrich's response to these specifics is to say that everything he describes is accurate, only that it didn't necessarily happen to the people, in the places, or at the times it occurs in the book."
Come on, if a writer is going to do this kind of thing, why not just use the material in a piece of really good fiction?