The big song of the Avengers 2 trailer was the creepy, ominous Pinocchio music, acting as a metaphor for Ultron's refusal to be "a puppet." But you know what OTHER song goes super-well with the trailer? Celine Dion's "My Heart Will Go On" - also known as the theme to Titanic. Don't believe me? Skip to the :37 mark and let the magic wash over you.
"I want you to draw me like one of your French robots." - Ultron