This is such a hard question because I love them all for different reasons! If I absolutely had to choose, I'd probably go with Deathly Hallows Part Two. It's kind of a cliche answer, but there's something so special about it. I think it's the Pensieve scene that puts it at the top of my list. The acting in that film is truly phenomenal, as well. I get goosebumps just thinking about it!