Guardians of the Galaxy: This may not be close to the comics at all but the acting and action is great. It's also really funny. It should be on the top 3.
Captain America: The Winter Soldier: The action in this movie puts every superhero movie before it to shame. Steve Rogers is not a boyscout, he is a bad ass.
Avengers: Infinity War: A villain protagonist, a lot of depth to the plot and some extremely heartfelt moments. An unprecedented cinematic experience.
Iron Man: Come on Iron Man was the Launching event of what's known as The Modern Day Star Wars "Marvel Cinematic Universe" also Rdj is brilliant.