While I would have liked to see Tom Bombadil, I realize that it isn't really necessary to the story. Same goes for replacing Glorfindel with Arwen, taking Frodo to Rivendell. They're extra characters that don't end up doing anything for the rest of the story.
For Two Towers, yeah, Elves showing up at Helms Deep was a little off, but it helped illustrate Galadriel's confidence in Aragorn and Men, as opposed to Elrond's skepticism. Elrond is finally convinced in Return, and is starting to be convinced in Two Towers. In Fellowship, he was certain that Middle Earth would fall to darkness, and was only concerned with getting the Elves out.
Faramir gets a little more depth in the extended edition Two Towers, showing that all he wants is a little praise from Denethor, but never gets it. Not exactly how I remember things in the book, but it better explains the suicide rush. Also, Faramir is described as a Captain loved by all the soldiers of Gondor, but I haven't really seen that in any of the movies.
One thing I wish was included (and it wouldn't have been very long, either), is showing Wormtongue hurling the palantír at Gandalf, et al. Instead, Pippin just finds it in the water.
Also, maybe it's just because I read the books, and know that Éowyn and Faramir end up marrying... but it seems like they're "together" at Aragorn's crowning ceremony, but no explanation is ever given in the movie. I'll have to see if anyone who hasn't read the books noticed the same thing.
Otherwise, I think the movies were as faithful as they could possibly be to the books. Really, I'm just glad it was Merry and Éowyn who killed the Witch King
Re: OT- LOTR fan discussion thread - SPOILER WARNING
Threaded Mode