Bourne Trilogy: I really liked the films - all three were excellent.
Then I read the books. Not so excellent, in fact just plain bad. I found them dull, long-winded and tedious. There were rather dated as well. I don't often give up reading books ("War and Peace" aside), but I was sorely tempted to for each of these three books. Still, I persevered. Wish I hadn't now.
The Lincoln Lawyer, by Michael Connelly is a good book and the film (with a very well cast Matthew McConaughey) is almost identical. That's no bad thing really.
I really must read more of Connelly's work actually.
(Children/Teen/Adult) Hunger Games and Harry Potter series= Splendid books and splendid movies, perfect characters in the movies. The last movies can seem a bit dull, but I haven't read the last books so I don't know if they are dreary as well.
(Adult) The Railway Man= Difficult book to read, but still good, good movie but not really based on the book. The movie is mostly of the main characters torture, but the book is much more than that.
(Children) Molly Moon and the book of hypnotism= excellent book series, horrible movie of the first book. Not worth watching.
I watched the movie first (as a hu-uuuge Tom Hiddleston fan) and was kind of confused by the ideologies they were trying to portray. Picked up the book and everything made sense, so much so that I now respect the film a lot more. But the film on its own does not live up to the story at all.
For me it has to be Battle Royale by Koushun Takami. Great book and the film is one of my all time favourites. I can also recreate it through the PC Game Battlegrounds!