While athletes, movie stars and other celebrities can earn very high incomes, the majority (61%) of very high-income people (> $1,246,000) work as corporate executives or in the finance industry.
When you account for all taxpayers with income greater than 1.2 million a year, the list includes: Lawyers; Medical jobs; Real estate jobs; Entrepreneurs; Business operations; Computer, math, engineering, technical jobs; Skilled sales; Professors and scientists; Farmers & ranchers
Data source: Jobs and Income Growth of Top Earners and the Causes of Changing Income Inequality: Evidence from U.S. Tax Return Data (pdf)

ADDED NEW VERSION 2/10/2009
Recently the CBO published a supplement to their Historical Effective Federal Tax Rates: 1979 to 2005 report to include a breakdown of top 1% into smaller percentiles. I took the data for income and created this visualization. It is comparing the minimum income for each percentile to the average income in that percentile.
UPDATED VERSION {Click on the image to take a closer look}

ORIGINAL VERSION {Click on the image to take a closer look}

Data from Congressional Budget Office
[tags]United States, High Income[/tags]
This graph shows the different types of income of the “Top 400″ from 1992-2005. Number one source of income is Capital Gains, which accounts for more than 50% of their income in 2005.
The “Top 400″ are the 400 tax returns with the highest adjusted gross income reported to the IRS.
{Click on the image to take a closer look}

Data from the IRS via Wall Street Journal’s Tax Report
[tags]Tax Rates, United States, Income tax, IRS[/tags]
This graph shows the average income reported to the IRS and the average taxes paid by the top 400, i.e. the 400 taxes returns with the highest adjusted gross income from 1992-2005. This does not represent not gains in the wealth of people like Bill Gates but instead shows the annual income of the superrich reported to the IRS. They accounted for 1.15% of total income reported in 2005, more than twice as large as their 0.49% share in 1995.
{Click on the image to take a closer look}

Data from the IRS via Wall Street Journal’s Tax Report
[tags]Tax Rates, United States, Income tax, IRS[/tags]