No major spoilers, but I didn't really work to hide what's going on
I went to see Harry Potter and the Half Blood Prince last night, in 3-D. Let's start with the 3-D part -- it's a bit of a rip-off. It's cool for as long as it lasts, but only the first 20 minutes of the movie or so are shown in the extra dimension. Lame.
The movie itself I liked -- not surprising, since I thought Book Six was one of the highlights of the series. But even one of my friends who said he thought the book was one of his least favorites (he said the least, until I reminded him of the 5th installment: "Harry Potter and the Post-Pubescent Angst") thought the movie was one of the better ones out there.
Harry Potter and the Half Blood Prince begins with HP getting royally cock-blocked by Albus Dumbledore. This theme (teenage romance and cock-blocking) will reappear as a side-plot throughout the film, and it is a solid if not spectacular presentation. Hermione enslaving a flock of birds and sending them on kamikaze runs against Ron was a highlight. On the other hand, when Ginny finally decided to hook up with Harry in the Room of Requirement, I really wanted it to transform into a 70s-style love nest. Kids need to mack, god dammit!
The main portion of the movie was done quite well. Alan Rickman as Snape was brilliant, as always, and I continue to be a fan of Helena Bonham Carter's portrayal of Bellatrix Lestrange. The three main characters can't compete at that level, but they have all blossomed into at least passable actors, and that's a good thing (and, for those of us who remember Sorcerer's Stone-era Daniel Radcliffe, a surprising one as well). The movie's vibe really felt like the Lord of the Rings at times, and I mean that in a good way (Jim Broadbent's uncanny resemblance, in my view, to Bilbo Baggins may have contributed to this). Compared to the Order of the Phoenix, I think the director did an excellent job making the minor tweaks to really make things shine. Luna Lovegood's character was a joy to watch (I didn't feel like she was overdone like last time), and the magical scenes no longer had the feel of Final Fantasy boss battle. The fact that the plot didn't require the main characters to be annoying and angsty was a great benefit, and the movie had an overall lighter tone that was greatly appreciated. And there finally was an indication that maybe adults are better at magic than Harry Potter is -- watching Harry's spells get impetuously swatted aside by superior wizards was a great highlight.
The climatic scene (you know the one I mean) was a bit of a letdown, though it was operating under some heavy constraints given the nature of a book-to-movie adaptation. It just didn't have the punch I'd have expected out of it. Malfoy was pretty flat throughout the movie (though he seemed to have gotten the number of Voldemort's extremely snappy tailor). Indeed, I'd say the movie fizzled a little bit at the end, though not enough to take away from an overall enjoyable experience.