For me it’s Spider-Man’s. It’s bouncy, upbeat, triumphant, and energetic and I can’t wait for it to reprise in No Way Home when I see it. Shang-Chi, Captain America, Wanda, and Ant-Man’s themes come close
On the villain side of things, it’s a tie between Thanos and Mysterio.
Thanos’ theme is eerie and foreboding, showing how menacing he is and how he means serious business.
Mysterio’s theme is heroic and upbeat at first, with almost a sense of melancholy due to his backstory about the Elementals killing his family. However, after his reveal, the music takes on a whole different meaning. It’s as if the song itself is part of the illusion. At the end of the movie, in the infamous mid-credit scene, the same orchestration is there but it no longer has that heroic feel to it. Now it feels like dread and despair and menacing as the score punctuates the horror of his actions.
