47. Mark Zuckerberg
Say you're worth, oh, $17.5 billion. Would you wear a hoodie, old tee shirt, and adidas sandals every day? Mr. Facebook will probably protest that fellow zillionaire Steve Jobs wore a simple black turtleneck every day… but we did some research, and Steve's go-to getup was not too shabby — those Issey Miyake-designed suckers cost $175 a pop.