I definitely give a book more than one chapter. A good example for me would be "The Girl With the Dragon Tattoo." It started out very slowly, and pretty boring. Then it picked up, and boom! I couldn't put it down, and read straight through it and the next two books. Sometimes it just takes a while to get the stage set...
Edit: I liked "The Help," but it's very "regional," for lack of a better word. Maybe it resonates more with people who grew up in the Southern U.S.?