Introverts make great business leaders. They think before they speak, they tend to be more calm, and they don't usually get involved in office political and social drama. I recently viewed this video of Susan Cain at TED titled "The Power of Introverts" and found it to be QUITE fascinating!
When I first figured out that I was an introvert, it literally changed the way that I saw myself, both at work and in my personal life. I actually think that a lot of salespeople - GOOD sales people - tend to be more introverted. They listen to the customers needs, tend to focus on truly helping their clients instead of trying to be their friend, and they often step back to see the big picture rather than making the quick buck on a deal.
Have you taken any personality tests? Are you more introverted? Or extroverted?