oh wow. i thought they did a fine job leaving out bombadil his little acid trip of a couple chapters added nothing to the book and was fine being left out of the movie. i remember commenting on it to a friend of mine as we were leaving the theatre and he agreed, taken out because it was unimportant.
potter book --> movie is alright, but nothing spectacular. like most book to movie adaptations i think they'd be better served becoming a mini series instead of just one shot movies.