What should the role of the “Rich” in our society be?

There continues to be this notion that the “Rich” (however you define it) are not paying their “fair share” of Federal income taxes.  This notion persists even though roughly half of all Americans paid no Federal income tax in 2010.  This leads me to wonder:  is the role of the rich to work hard and then have a significant portion of their earnings given to others through the force of law?  Should they be allowed to hoard their wealth at the expense of providing a safety net for others?  What role should the rich perform in our society?