Steve Rogers: Big man in a suit of armor. Take that away and what are you?
Tony Stark: A genius billionaire playboy philanthropist.
A reflector screen is visible on Hawkeye's sunglasses at the very end when Thor and a restrained Loki are returning, presumably, to Asgard.
While on the helicarrier, Tony Stark is wearing a Black Sabbath T-shirt. Black Sabbath is the band who sung the "Iron Man" song.