Melinda Gates, co-chair of Bill & Melinda Gates Foundation

Net Worth: Melinda's husband Bill, is worth $61 billion.

How She Got To Where She Is: Melinda got her start developing products for Microsoft, but eventually switched her focus to the charity, with Bill doing the same a few years later. By 2000, the Bill & Melinda Gates Foundation had merged with the Gates Learning Foundation and was fully up-and-running. Since then, the foundation has donated around $800 million annually to organizations and charitable causes ranging from vaccination research to increasing rice crop production.

Notable Accomplishments: Melinda has done so much good for the world that she and Bill have both been named Time's Person Of The Year, received the Order of the Aztec Eagle for their beneficial work in Mexico, and were given honorary degrees from the University of Cambridge after their $210 million gift aided foreign students in attending the University.

And That's Not All... Melinda serves on the board of trustees for Duke University and the board of directors for the Washington Post company, and previously sat on the board for Drugstore.com. And, on top of that, she still helps out with her Alma Mater, Ursuline Academy of Dallas.

Key to Success: Give Back. Melinda has made it her life's work to help others in need and look for solutions to help others in the future. From forming competitions and obtaining ideas for new toilets that could improve sanitation to investing in microfinance and microloans to assist underprivileged women entrepreneurs and individuals, even small ideas can change lives. We're particularly intrigued by her newest campaign for global access to contraception.

Photo: Kay Nietfeld/dpa/Corbis