Forbes' world billionaires list released

Microsoft giant Bill Gates held the title for more than a decade, but he's dropped to number three.

The new number one guy is investment guru Warren Buffet, worth $62 billion.

Number three is Mexican telecom mogul Carlos Slim, worth $60 billion.

Of the top 20 self-made billionaires, only four live in the U.S.

Fifty are under 40, including the youngest ever: 23-year-old Mark Zuckerberg of Facebook.com, worth $1.5 billion, and single.

The World's Billionaires