Bill Gates-World's biggest philanthropist also devoting $27 billion to good deeds. Bill & Melinda Gates Foundation fights infectious diseases (hepatitis B, AIDS), funds vaccine development, helps high schools.
Paul G. Allen-His Paul G. Allen Family Foundation has donated heavily to education, art and science causes.
Pierre M Omidyar-His Omidyar Network invests in microloans to small business owners in developing economies and in open-source software. Once promised to donate all but 1% of wealth to philanthropy. Now says he will use his entire fortune to "do good."
Eli Broad-Big arts collector, benefactor: recently gave $60 million to the Los Angeles County Museum of Art.
Gordon E. Moore-Moore would be worth twice as much, but in 2000 he donated half his Intel stake to charity-environmental causes and education, including $300 million to his alma mater.