I liked the film version of Harry Potter and the Half-Blood Prince more than I expected to. Some really nice little comic moments, some effective tear-jerking bits, and (as expected) a chance for Michael Gambon to play a bigger role than in the previous films. As usual, a lot of plot from the novel bit the dust, and there were a couple of new film-only scenes, but it seems as though most of the real highlights were there. The child actor playing Tom Riddle (who's apparently Ralph Fiennes' real-life nephew) is uncannily good, in a creepy, reptilian way... though he does have a nose. And the girl who plays Luna Lovegood is still one of the series' great secret weapons in my opinion.
As an added pleaure, all the children in the cinema were silent as the grave, just as with the previous HP films I've seen on release.