I finally saw it last night, and honestly I was a little disappointed. (Not enough to NOT buy the movie when it comes out, but I definitely thought this would be my favorite movie, and I think it ranks third!)
I went with a group of friends, most of us who have read the book, and as the credits were rolling we were discussing the idea of the movie being filmed so you wouldn't have had to read the book to understand. One friend brought up a good (if small) point: if you hadn't read the book, you didn't really know that the Durmstrang students were on the boat, and the Beauxbatons (sp?) were the ones in the carriage (unless you caught their headmaster's talking about the care of the horses, which was kinda lost in the activity of the opening banquet).
And what was with the dance class, or for that matter, the Yule Ball? Completely not what I expected - and weren't Harry and Ron's dates (in the book) in different houses - one Ravenclaw, one Gryffindor?
There were a few parts where I got freaked out, but maybe if I saw the movie again it would get better (we had a group of younger individuals - high or middle school students) sitting behind us and talking loudly, making stupid comments, or laughing at something else they were doing in the middle of some of the more "suspenseful" moments of the movie
)