1. 1. Mark Zuckerberg, Facebook
Grey t-shirt, jeans, Adidas sliders or Brooks' trainers dependant on the weather. He told the Independent: "I really want to clear my life so that I have to make as few decisions as possible about anything except how to best serve this community.
"I feel like I'm not doing my job if I spend any of my energy on things that are silly or frivolous about my life".