Ireen asked me afterwards whether I remembered anything from the book which wasn't in the film, or not completely so; I must say I didn't notice anything in particular. On the other hand, it's been a while since I read the books.
My favourite scene was at the end, when Dumbledore announced that in celebration of the events, exams would be cancelled. Students cheered -- except for Hermione, whom one could see saying "Oh, no" :)
What I was a bit disappointed with was how Harry killed the basilisk -- the sword looked very light and the blow he killed the beast with was rather pitiful IMO. (And the blade didn't seem very sharp, since later on Harry grasped the sword by the blade.)
The boneless arm effect was rather interesting ;)
On the whole I thought it was OK. Oh, and I think Hermione looks kind of nice -- certainly, her teeth aren't as big as they are portrayed to be in the novel.