I thought it was a little too heavy-handed on the uses of clock-like devices, and was particularly disturbed by the enormous pendulum which swung back and forth over the entrance they kept using. I also thought the werewolf looked a little cgi-stupid, particularly when compared to Sirius' variant. Much as I loved what Emma Thompson did with Professor Trewlawney, I'm not sure any of the Divination class scenes were actually necessary for the movie; but more world detail is good.
Also - the entire animagus reporter plot was cut from the movie. In general, it's extraneous material but, as C. has observed, it does add a crucial extra element which isn't really in the book otherwise: the way events at Hogwarts can have major effects on the entire wizarding world. It's a gentle introduction for the increasing level of politics in the subsequent books.
My favorite job from the credits: Creature Hairstylist.
