Couple of stray thoughts...
(1) A good example - as if we needed any! - of why reading a book, and seeing a movie based upon that book, are two very different experiences, ESPECIALLY if the book in question is lengthy and "detailed". Inevitably, SOME backstory, some fleshing out of characters, etc, has to be sacrificed in trying to make a movie of manageable length. This is NOT a criticism of the movie, by any means. And not a novel observation, certainly. Just noting that the movie does a good job of moving the "movie storyline" ahead, and of summarizing a very detailed book into a "bite sized" format.
(2) Enjoyed the movie, quite a bit. Of the books, this was, for me, the least... er... I don't know... upbeat? Whimsical? By design, granted, as Harry is feeling dissatisfied, isolated, somewhat "left out", angry, frustrated, and so forth (while the HALF BLOOD PRINCE is hardly light fare, I don't think it has nearly that air of stifling frustration), and I think the movie reflected that.
(3) I do wish they had mentioned that Trelawney (SP?) was the source of the prophecy in question, and had perhaps given a bit more weight to its significance (to Voldemort, at any rate!). She is, granted, not a really central character, per se, but her role re the prophecy casts her in a very different light (in the movies she tends to come off as almost wholly incompetent, IMHO)...
And... treading carefully here... I am not one of those who feels one must "choose sides" when it comes to movies/characters. As a fan of comic books, science fiction, fantasy in general, I was looking forward to all the summer genre releases, and hoped all would be entertaining (and for the most part, I have been satisfied!). I was looking forward to Spiderman 3, Fantastic Four, Transformers, AND Harry Potter. So, PURELY IN THAT CONTEXT... I think I had a better time at TRANSFORMERS than at Potter, and maybe than at Spiderman. Not saying TRANSFORMERS is a better movie, because Potter (see above) was a segment in an ongoing story, and it was a darker, more downbeat segment of that story... and Spidey 3 was somewhat similar. Maybe I just liked the more upbeat nature of TRANSFORMERS, and the novelty. I definitely think TRANSFORMERS was the most fun of the big genre releases this summer (again...not getting into the whole "who is BETTER" thing! ... just based on "fun" quotient!)...
Shadow