I agree with Elladan:Elladan and Elrohir's part and that one with Bombadil and Shire shouldn't miss the film.
The part I missed to see the most was the taking out of the barrow downs section of the book. The Barrow Downs are probably my most favorite place in the entire trilogy and I was sad to not even see a deleted scene of it on the DVD. A truly great loss. And what do you mean by" the Theoden exorcism"? And I absolutely agree with you curunir's bane. I actually didn't like that part in the book.
I really have a serious problem with the way evil is presented altogether in the films. In my opinion, the bad guys were a lot more menacing in the books. The scene with Viggo Mortensen hurling a torch into the face of the King of the Nazguls might be cool to look at, but it does very little to inspire fear in the villains.
Helm's deep could have been made so much more epic. In fact, the movies in general, despite how epic they were, could have been made SO much more epic.
I didn't really miss the Scouring of the Shire ( I still liked it though- esp. hoe Merry and Pippin become famous and Frodo doesn't) Also I can see why Tom and Faramir were cut/changed, and Theoden's exorcism is one of my favourite scenes. What I did not like was the look of the army of the dead- I prefer the books description. I also miss the part where it reveals that Denethor has a Palantir, and Sauron has been using it to make him give up hope. I also hated the Elves at Helm's Deep, Anduril FedEx etc. There are others but I cant think of them just now.
Tom Bombadil is what I missed the most. He was AWESOME and actually one of the only parts of the books that I still remember well (read them when I was like 10). I was so disappointed when it wasn't in the movie...
The biggest letdown for me was the way that they seemed to "scrunch" up the end of Return of the King. THe books gave a lot more attention to the events after the Pelennor fields and after Frodo gets attacked by SHelob, but I felt like the movie just sort of summed it up a little too much. I know a lot of story happened and they didn't have 7 hours to tell it, but still. I also hated the way they made Frodo turn on Sam and follow Gollum. Just stupid.
Frodo, you weren't supposed to leave straight after Bilbo, but a few years later. Sam and Frodo, those Elves you saw in the forest would have welcomed you. Where are you Tom Bombadil? Lady Galdriel, you got some of the wrong presents. If I were you Haldir, I'd stay in Lothlorien. Eomer, did you miss your train to Helm's Deep? It was supposed to be Erkenbrand coming from there. If I were you Grima, I wouldn't stab Saruman. If I were you Saruman, I wouldn't go bungee-jumping without an elastic. The Bttle of Pelennor Fields was not for you "the dead", but for the living of southern Gondor. You damn Frodo, you never got that angry with Sam! Saruman and Grima, you died too early to scour the Shire. Well... That's just about the main parts
bombadil missing seed and dust from garden missing for sam the dead showing up at minas tirith stupid death for saruman whoever said sauron himself was just an eye? his symbol, maybe, but himself? frodo, you're supposed to take sam with you into shelob's lair.