It was a decent movie that I overall enjoyed, but it just didn't have the 'magic' of the other films.
Harry Potter and the Half-Blood Prince is a dark tale. The movie tried to be very dark, which it succeeded at except for the running gag of 'hormonal' innuendo which to me got very old very quick. It seemed like humor was forcibly thrown in to keep the story from being too depressing. This is a dissapointment...while the book does the same thing (but much more successfully), in the movie it simply did not work.
I'm still looking forward to the final two movies. But overall, I was not too impressed and am disappointed in the movie adaptation of Harry Potter and the Half-Blood Prince.