Without a doubt America's most successful investor, Warren Buffett released his much anticipated annual letter to his shareholders about Berkshire Hathaway's performance, reporting a net worth gain in 2006 of $16.9 billion, an 18.4% increase.

With Berkshire Hathaway sitting on $42 billion in cash, shareholders and investors alike pour over his missive every year, searching for guidance on where and how Buffett finds value.