Having seen this marvelous film now, one can be even more enthusiastic about Williams' score. Like many who have written here, there was a marked feeling of letdown in Chamber of Secrets, so the waterfall of new, varied, and deeply felt music that comes with this film is welcomed. By the way, anyone wondering whether to see this film is encouraged to go: Cuaron's work is among the best there is in film today, and his evocative, dramatic direction clearly inspired Williams. As to the music, it's every bit as breathtaking as some of Cuaron's shots. The Buckbeak music (especially while watching the magnificent flight scene over the lake) is sublime, and the juxtaposition of period-instrument pre-Baroque, Cantina jazz, and that Prokofiev-style orchestration of Williams is deeply nourishing (does the snowball fight scene remind anyone else of the Classical Symphony?).
For Potter fans and simply lovers of art, this music and its film are both unreservedly recommended. They are exemplary of how artistic inspiration comes from the formless realm of consciousness and penetrates through a multiplicity of people and their artistic media--starting with Mrs. Rowling's writing and working through to Cuaron, Williams, and the splendid cast of this film. It all began, about 15 years ago, on a simple train ride from Manchester to London.