Course with LotR, I seriously doubt that everything could have got included... And trust me, I noticed. I made the mistake when Fellowship first came out of re-reading it before the movie came out. It was fresh in my memory and every slight difference I noticed. It all stood out like a sore thumb, and I debated many of the plot differences, different feels for characters and character development (Frodo struck me a bit different from the book for instance, also as a bit wiser and less uncertain of himself, and I don't remember in the books that Elrond had as much an issue with humanity), etc.
Something I wouldn't recommend doing, and something I didn't repeat when the Two Towers and RotK came out... I was able to enjoy those 2 movies (and the first at a latter time) more, when the book wasn't fresh on my mind and all...
I'll probably go to see the new Batman movie when it comes out, and there were some others in previes that I'm thinking of going to see.