Who pays more in federal income tax, your grandma the plumber/teacher of the disabled and infirm, or Warren Buffett? Take a look at this link (from Greg Mankiw's Blog) to the Effective Federal Tax Rates based on income.
The lesson: The wealthiest pay 30.4 of their income to their government. The middle income distribution pays 14.1. So...billionaires already pay more than secretaries.