Of all the major superheroes, Iron Man seems the most realistic. He relies on real-deal technology to get the job done, not being from another planet or a bite from a radioactive spider. And while the technology to make a real Iron Man suit doesn't exist yet, it's getting closer.
As a part of the Iron Man 2 DVD, they sent actor Clark Gregg, who plays Agent Phil Coulson in the movies, to check out Raytheon's new XOS 2 robotics suit, which is the closest thing we've got to an Iron Man suit. The wearable contraption gives the wearer a whole lot of extra strength for lifting and carrying things. It's very obviously lacking the ability to fly and to shoot missiles out of its arms, but we all know that it'll get there eventually.
Via Danger Room