This was the topic of a recent article in the Houston Chronicle called Got $5 million? Consider yourself rich, experts say. Here is a brief exerpt of the article:
"most people in finance use the $5 million mark, and apparently others agree. In a January telephone survey of 253 people with at least $500,000, 45 percent said it takes at least $5 million to qualify as rich.
Another 25 percent said $25 million, and 8 percent picked $100 million, according to the Spectrem Group, a consulting firm that specializes on research about wealth. For the Internal Revenue Service, earning $349,700 qualified for the top-tier 35 percent tax bracket in 2007.
The Securities and Exchange Commission, meanwhile, requires individuals to earn $200,000, couples $300,000 or households to show they have $1 million in the bank before they're considered wealthy enough to safely invest in lightly regulated instruments like hedge funds.
The U.S. Census Bureau, which in its most recent annual Current Population Survey in 2006, estimated that 2.3 million households — or 1.9 percent — brought in at least $250,000, the highest figure it measures."