Here's my review...
This film has the necessary elements to not totally piss off those who have read the book and it will totally intrigue those who have only seen the movies. What does that mean? It means it has the action, story, special effects, and comedy to make a well rounded film that is quite enjoyable.
The book that is paired with this film centers around the development of young Lord Voldemort (or Tom Riddle). Its focus is on his family history and difficult childhood. This film misses out on a lot of character development of Tom Riddle. However, I contend that the film series provides enough information to show that Tom Riddle is extremely evil and had a troubled past before even attending Hogwartz. I will also state that the film only has a limited window and has to catch your attention much faster than any book (books are usually drawn out with extra details and unnecessary information). Having said that, let's get to the review.
Harry Potter and the Half-Blood Prince is probably the second best movie in the series (this is not to say that it was the closest film to its respective book) after the Prisoner of Azkaban. It has suspense, story, action (am I repeating myself...thought so), etc. The film begins with a great opening sequence of Death Eaters attacking both the Wizard world and the Muggle world. And from that the film really never slows down. I think they did a great job of explaining the Harry and Slughorn relationship as well as telling the story of Draco Malfoy. Some things were left out, but overall the film worked for me.
This movie will be a great summer film in a series of terrible summer films (Wolverine, Transformers [yes, too long, boring story...], etc.) and will be enjoyable for many folks. My rating? 4/5.