Reader's Choice: 3
Buffett spent much of the year enlisting his billionaire brethren to pledge the bulk of their wealth to philanthropy. But 2010 wasn't all about giving. He finalized the acquisition of Burlington Northern Santa Fe -- nice timing; with oil prices rising, rail's advantage is widening -- and tapped into Berkshire's $35 billion war chest to buy Marquis Jet. Then he surprised the world with a talent acquisition: He brought in little-known hedge fund manager Todd Combs to manage a chunk of the company's nearly $100 billion investment portfolio.