My students love the Diary of a Wimpy Kid books. I have only (so far) read the first one and I really loved how the author, Jeff Kinney, writes from Greg Heffley's point of view. The kids say all the time how they can relate to what happens to Greg.
The fourth book, still untitled, is due out Sept. 1st, with the fifth book coming out in 2010. I heard that the first book is being made into a movie. Some of the students agree with me that the movies they make from popular books don't compare to the books themselves. You don't get little thought bubbles over the characters head to see what they're thinking and there's not enough time in a movie to see the relationships built by the characters.
I haven't seen most of the movies made from books, but I do watch the Harry Potter ones- the next one comes out this month. I need to get out the other ones to refresh my memory in preparation of the movie opening.