I had a tough time choosing between Iron Man and Captain Marvel and ultimately voted Captain Marvel because I relate to it more, so it was a personal choice. But Tony was truly born as Iron Man two fold, one because of the very conscious choice to stop making weapons and therefor actually forging a path of his own, and making a suit in a freakin' cave. Steve was pretty much always Captain America in his heart, it's just no one else paid attention to him because of his size, Ant-Man is fun, but it feels more like a job he took on than an actual persona, and both Thor and T'challa were also already who they were, we just got to witness them both grow into the responsibility of leadership, (although T'challa did it in one movie where Thor took three... ;P ) Dr. Strange's story was good too, but to be honest his cloak was my favorite character in that movie, haha, so he doesn't get my vote. (I do love BC though. So it's not meant to be a slam on him.)