First, I would see it again. The effects and scenery was breathtaking. I do have several complaints and likes, though.
I was really upset they didn't show or in anyway talk about the Scouring of the Shire. We see the old man scowling at the 4 hobbits return, and then they're back in the Green Dragon as if they (to the hobbits left behind) never left. Sam going up to Rosie in the inn almost seemed put in there to assure everyone that Frodo and Sam weren't fags but just loved each other platonically. And Merry was supposed to be later known as "Merriadoc the Magnificent" in the Shire. Sam was to be Mayor about 5 times. The movie needed a better vehicle to show how our four hobbits grew in stature in the eyes of the Shire folk!
Minas Tirith was supposed to be depopulated of all women and children (by order of Denethor). Pippin had met a soldier who introduced him to his son, who Pippin befriended and was only one of a few children left in the city. I think they had too many women and children there in the movie.
The White Tree in blossom again in the crowning scene. OK, that was not bad, actually. But it was dead, and Aragon was supposed to find a sapling in the King's Seat on the mountaintop.
When Sam returns to Rosie after Frodo left on the ship--wasn't Sam supposed to be living in Bag End? Frodo left it to him in his will. Was that house different--not Bag End? It seemed so to me.
The Oliphants were so big in the battle scenes, but later when we see Pippin find Merry, the dead oliphant is about 10 times smaller, almost regular elephant size.
The Men of Dunedain were missing. In the book, Aragon had about 25 fellow Rangers join him and go through the Mountain of the Dead with him. I wish they had included them.
In the book, after Sauraman's defeat at Isengard, there is a very heavy feeling of urgency to assemble Rohan and go to the aid of Gondor. Instead we see feasting and Merry and Pippin dancing on tables and Theoden vetching about Gondor not coming to his aid.
Legolas climbing up on the Oliphant was awesome. However, didn't we see a similar scene in Star Wars "The Empire Strikes Back" with Luke climbing up a land walker the same way? Still, a very cool scene. Legolas was very well played in all the movies. Orlando Bloom did an Oscar winning job!
The whole Hidden Staircase and Shelob's lair was awesome, but I would have left Sam going in with Frodo, too.
The movie didn't show all the orc's fight over Frodo's mithril mail, just two of them fighting over it. The whole scene made little sense to those who didn't read the book. It was too fast.
I thought Aragon was every inch the King. The movies showed his growth into the role very well. It was just different from the book, but played out well here.
As I digest what I saw today, I'll probably change some of my initial opinions.