It would have to be any 4 from Doyle (Harry In Winter, Foreign Visitors Arrive, and the climactic Voldemort track are all great), and "Possession" from Hooper's HBP. Doyle's soundtrack was absolutely ripped to pieces when it first came out. But when you look back at all 5 post-Williams soundtracks... Doyle's has the most, and the most memorable, themes. With "Family Portrait," "Buckbeak's Flight" and "A Window To The Past" Williams was moving towards a more melancholy and serious Potter, and Doyle continues very competently with tracks like "Harry In Winter" and "Voldemort." Hooper's two scores are usually mixed so low, and are so ambient, that they hardly make any impact (e.g. Dementors In The Underpass and much of the battle at the end of the fifth movie). When he does get thematic, with the Room Of Requirement, Flight Of The Order Of The Phoenix, Dolores Umbridge, Dumbledore's Army, Fireworks - all of these tracks have a sort of obnoxious obviousness and inappropriateness to them that makes them "pop out" of the film. "Possession" is one track that works very well. The building string lines and that beautiful bichord dissonance at the end, aptly communicate the emotion of the scene. Desplat's scores have been, to my ears, almost entirely underscore. I saw Parts 1 & 2 back to back and when it was over I didn't really have a consciousness of any theme, except there was some vague choir music associated with Snape. There was a lot of Remote Control type music over the battle sequences - loud, energetic, very appropriate to the scenes, but absolutely nothing to make it stand out and say "This is Harry Potter and not Movie X." Probably the best part of Part 2 was when they tracked "Leaving Hogwarts" over the epilogue. There was a feeling in the theater as if everyone had perked up and was listening with rapt attention. Despite the fact that music hadn't been in the movies for ten years... mostly everyone recognized it!