Being a genius billionaire superhero isn't all fun and games apparently. Sometimes there are people who want to question your ethics just because you've got a past as an arms manufacturer, and then there's always the chance you'll get the ever loving crap kicked out of you when some bad guys get their hands on a new bio-weapon. 
 This is one of the best Iron Man stories I've read. It came out a few years before the first movie, and the films would use several of it's ideas and overall tone. The third movie in particular uses the basic story elements. It also brilliantly set up a phase of Tony Stark in the comics for Civil War and its aftermath through Matt Fraction's great run on Invincible Iron Man.