I read Angels & Demons and I've watch the movie. I just love both of it book because I would say that they are different. To those who just watch the movie version here's what I could find out what you miss :
1. The first one to be killed was not Vetra's friend but her father Leonardo Vetra. Replaced by her friend Silvano.
2. Robert Langdon receives a phone call from his home and flew to CERN to look at the Leonardo Vetra's body and met with Vittoria Vetra there.
3. Langdon and Vetra flew to Vatican City by a shuttle-looking airplane that goes with the speed of Mach 11.
4. The director of CERN, Maximilian Kohler was removed. He was the one who got killed in the end accuse by the Camerlengo to brand him.
5. There are 2 reporters from BBC in the book that did not appear in the movie. We could see a lot of reporters from various TV stations around the glob but there is none from BBC which contrast with what is told on the book where it only focuses on BBC. These reporters communicated with the the so-called Illuminati leader.
6. The forth Preferiti is killed in the fountain but were saved and name Pope in the movie.
7. The Camerlengo and the previous Pope were actually blood related which what cause the Camerlengo to act immorally and commit suicide upon noticing it. This is the best part because a Pope is mistakenly seen as going against his celibacy but actually did a 'test-tube baby'. This is seriously challenging religion. Damn it.
8. Vetra was actually wearing shorts in Vatican which is actually prohibitted there for women there.
9. Langdon went together with Camerlengo in the last helicopter scene. Camerlengo survived with a parachute on a building and Langdon fall into water near an island.
10. In the movie when Langdon was asked by the Camerlengo about God, he answered that he was not ready about faith. In the novel Langdon answered that he ain't ready to believe in God because he cannot accept afford to accept that a God would punish those who did not follow His teaching.
There are lots of other thing which is different and removed and added in the movie. It won't be a waste if you read the book after you watch the movie.
Overall I sense that bot the movie and novel were really challenging religion as it plays with it a lot. Even though it does not involve Islam (there may be some things about Islam), the story challenges readers about the idea of "God" and divinity. Readers should take everything critically and be careful for anything that involves religion on philosophy.
Still the book is really good.
Looking forward for the next Robert Langdon adventure "The Lost Symbol" that will be released on September 15, 2009.