There's no getting around it: Iron Man is the most popular of the Avengers. Just look at the box office. 'Iron Man' and 'Iron Man 2' both broke $300 million at the domestic box office and 'Iron Man 3' passed $400 million. Robert Downey Jr.'s Tony Stark didn't just put Marvel Studios on the map, he's pretty much kept it on the map. It's safe to say that 'The Avengers' did as well as it did because Iron Man was front and center on all of the posters. People love Iron Man and that's okay.

But, while he's the most popular, he's not the best Marvel cinematic superhero. That honor belongs to Captain America.

'Captain America: The First Avenger' grossed a respectable but far from astonishing $176 million in the United States. In the numbers game, the super soldier from Brooklyn can't compete with the genius son of his old World War II buddy, Howard Stark. On paper, it's understandable. How could a square, humble and polite superhero possibly compete with the acid-tongued, heavy metal-scored, technological badassery of the 'Iron Man' franchise? Steve Rogers looks downright quaint when you put him next to Tony. He looks old fashioned. He's an antiquated hero from an antiquated age.

And, that's why he's one of the great cinematic superheroes of all time.

Chris Evans' Steve Rogers walks a very fine line. He's a good guy down to his core, a straight-shooter who always stands up for what's right even if it makes him the least popular and least cool guy in the room. In so many movie heroes, this kind of stoic allegiance to truth, justice and the American way is an albatross. It makes them seem dull and uncomplicated. it's why so many generic action movies feature instantly forgettable protagonists, but memorable villains. It's a battle Superman has to fight every day in fanboy circles -- boy scouts are boring. Everyone likes a bad boy.

Other Marvel heroes are born into great power or have power thrust onto them, often by accident. Cap was a good guy who set out to do the right thing and keeps on doing it, even when the world is against him at every turn.

But, Captain America transcends basic Hollywood goodness. He's unique because he's 100% defined by his old-fashioned nature and his earnestness and goodness make him a pariah in a world where characters like Tony Stark are worth more than double his value at the box office. As a man out of time, frozen and forgotten for nearly 70 years, he represents a mindset and philosophy that seems trite and simplistic to modern eyes. Steve Rogers' uncomplicated nature isn't the result of a manufactured and boring "good guy," but simply the nature of man raised to be polite and respectful in an age when that meant something and was commendable. By being a steadfastly uncomplicated guy in an extremely complicated world, he somehow loops around and becomes extraordinarily complicated.

Faced with a world that has moved on from every value that was instilled in him, Cap keeps on fighting the good fight. He keeps on wearing red, white and blue despite the fact that overabundant patriotism went out of style in the '70s. He takes things seriously and is taken aback when his compatriots do not. He's stiff and old-fashioned and seemingly uncomfortable with everything he encounters in the modern world. He doesn't crack wise in the face of evil like Tony Stark. When you've fought across a war-torn Europe against an enemy with nothing less than the total annihilation on their mind, you learn to show a little respect. His complete and utter simplicity, his lack of grey shades in a world dominated by the very grey likes of Nick Fury, makes him something truly special. He's complicated because he doesn't know how to be complicated.

Compare him to the other Avengers. You have Iron Man, the wealthy whiz-kid-turned-arms-dealer. You have Thor, a powerful Norse god and heir to the throne of Asgard. You have Bruce Banner, a tortured genius with a big green problem that haunts his every moment. Compared to their high concept origin stories, Captain America's simplicity is just plain moving: he was a weak guy who became strong without ever forgetting what it was like to be weak. Other Marvel heroes are born into great power or have power thrust onto them, often by accident. Cap was a good guy who set out to do the right thing and keeps on doing it, even when the world is against him at every turn.

That's powerful stuff and indicative of the American spirit in the 1940s. The definitive scene in 'Captain America: The First Avenger' isn't Steve Rogers getting super soldier serum injected into his body -- it's him pre-transformation, jumping onto a grenade to save his comrades without a second thought, unaware that it's a dud. This kind of self-sacrifice comes naturally to Cap. It takes a Loki-led Chitauri invasion of New York City for Iron Man to learn the same lesson of self-sacrifice.

There are no weak links in the cinematic Avengers line-up. Every character and every actor is fantastic and they're a joy to watch whether they're together or apart. But, even with the bombast of Thor and Iron Man and Hulk, I keep on coming back to Captain America as the guy I like watching the most. I find his selfless courage inspiring. I find myself humbled by his sincerity. I find myself ticked by the fact that he still calls his allies "ma'am" and "sir." In a movie universe filled with robots and aliens and gods, he's a necessary moral center and the only Marvel hero fully equipped to cut through all of the BS. He's not the Avenger I'd want to be, but he's the Avenger that we should all be.