The short-short-short review: I thought the Half-Blood Prince (HBP) was a great movie...of course.
Please be advised, the follow review contains spoilers.
I came into watching the movie as a fan of the Harry Potter movies and realizing that there was no way they could fit all the details of the book into a movie. This perspective, perhaps, helped me to enjoy the movie as a regular movie-goer rather than as a harsh critic waiting for the movie to screw up a small detail.
The first thing that struck me as I watched the movie was how the actors have grown into their characters. The movie was so tight for me that I truly forgot I was watching a movie and felt like terrific summary of the sixth book. It hit most major plot points from the book, and to me, never felt rushed. The movie had time to go at a normal pace and helped develop the relationships between the characters.
Relationships
One of the things I was most curious was how the movie makers were going to develop the blossoming relationship between Harry and Ginny because in the books we are allowed to hear Harry's internal monologue. We see the internal beast growing inside him for Ginny and know the fierce debate going on in his head.
I think that the growing relationship between Ron and Hermione was been way more interesting and more apparent throughout all the movies (just like in the books, well from book 2 and onwards). The actors have been really growing into their roles as well. It's a joy to watch them onscreen. My only curiosity is how the actual scene will look like when Ron & Hermione finally do kiss, because in the books the straw that broke the camel's back was as a direct result of Ron showing empathy for the house-elves (which Hermione was fiercely fighting for equal rights for elves....ie S.P.E.W.). This scene wouldn't have the same impact as it did in the books because SPEW was cut out entirely in the movies (poor house-elves...they really did get the shaft in these movies).
Quidditch
I loved the quidditch scenes (try-outs and one game), even though they weren't very prominent, but the scene was so well done that it really felt like watching a real sport. It had the grit and fight of a soccer match, combined with the grace and style of an Air show. This is a sport I would definitely love to watch in real life.
Horcruxes
I'm just going to say a quick thing about the mission that Harry has before him. It's great that we learn what a Horcrux is, however, I'm sad to see that the other possible Horcruxes aren't revealed. The audience has no idea that Tom Riddle sought important items that were related to Hogwarts to make as horcruxes. So at the end of the movie, we're not left with the mantra that will lead to the next book/movies: "the locket, the cup, the snake, something of Gryffindor’s or Ravenclaw’s"
The Ending
Which leads me to the ending of the movie. Some people have already voiced their opinions that they didn't like the ending, that it was a bit anti-climatic. I partially agree with this statement, however, I actually felt exactly the same way when I finished the 6th book. It is true, however, that we got to see Dumbledore's Funeral at the end of the book,"The White Tomb"(which is actually important for the next book), but the same sense of loss was apparent when I finished the 6th book. It was very touching to see the Phoenix Lament and showing Dumbledore's sleeping portrait in the Headmaster's office, which gave me the same feelings as the book.
Conclusion
As I said before this movie to me was really great, I throughly enjoyed everything about the movie, and while I can find some nitpicking, I do it for the sake of writing a review and revealing my experience with the movie. In retrospect, after reading all the books several times over, I regard the sixth book as almost a two part story: where HBP is learning about Horcruxes and what they are, and Deathly Hallows (DH) is about actually finding & destroying them leading up to the final fight. The same can basically be said about this movie. Since the last book will be split into two movies, I considered the HBP movie to be part 1 of 3 before even seeing it. I find that my assumption was spot on, it definitely felt that way to me at the end of watching the movie.
If you haven't been watching the other movies, I know that you will be lost watching this movie, but for everyone else, I'd HIGHLY recommend watching this movie. To me, it was the bee's knees.
---------------------------
A little background for those that don't know me: I'm a huge Harry Potter fan. I've read and re-read all 7 books so many times I've lost track. I never thought that I would have become such a huge fan years ago. The first book that I read was the third book, after I watched the second movie. I have always heard so much about the HP books that i decided to give it a go. I was so hooked by the third book that I kept reading and never stopped. I own both versions of the audio book series, read by Jim Dale and Stephen Fry (both are great for their own reasons, but I think I like Stephen Fry's the best). Jennifer and I listen to the audio books 30 minutes at a time while drifting off to sleep. When I'm not falling asleep, I also read the books in parallel with the audio books.