I think anything that's based on a source material you know THAT intimately is always going to be a disappointment.
I was lucky in that respect, that when I saw the films I had recently read the book, so it was fresh in my mind, yet not ingrained to such an extent that it provided a distraction to me.
IMHO Jackson, Walsh and Boyens definitely did a great job seperating the wheat from the chaff, I mean, what did Tom Bombadil REALLY add to the story?