Un-fucking-believable.

Jackson did a wonderful job bringing everything to life. I really enjoyed the extra bits of visualized events that were only related as a dialogue in the books, such as the battle against Sauron in the opening, the capture of Gandalf, and (especially) the uprooting of Isengard. The elves were nicely magical and etherial, and the orcs were suitably nasty. The balrog was amazing, the way the smoke and fire swirled and combined to form the demon. Very well done. I would have sat through 4 hours if Jackson would have done them. :-)

I agree with Thane on the ending. It worked, and it needed to be done for the movie. Whether Aragorn knew or not didn't really matter. The only problem with that scene was (as someone else mentioned) the difficulty of telling who was fighting at any particular point in time. Having Aragorn do some fighting added a bit of excitement but didn't really take any more time. Legolas and Gimli fight in the book, so they should have been fighting in the movie.

The addition of Arwen was a non-event. She was such a small part of the film that there was no appreciable impact. I didn't care for the way Narsil was just shown on the altar... Aragorn was carrying that sword around most of the time in the book (and he scared the hobbits with it in Bree by showing them the hilt :-).

The only part I really didn't care for was that stupid, cheesy tilting staircase in Moria. The whole Moria bit was exciting enough in the book without inventing things.

I need to go see it again. :-)