CEO and president, Hewlett-PackardRank: 14Why he matters: Wonder what happened to Michael Dell's mojo? Look no further than Mark Hurd. This year the chief of Silicon Valley's top-selling company stole not only Dell's crown in the PC business but also his reputation for ruthless efficiency. What's more, under his unflappable leadership, HP's stock price has doubled, and the company has emerged largely unscathed from its embarrassing reporter-spying scandal.
There's still plenty of tough sledding ahead; to achieve revenue growth of just 5 percent, HP would have to add a whopping $5 billion a year in sales. But then again, that's exactly what it did last year.
Meet 50 Who Matter winner Gina Bianchini. Her site, Ning, lets anyone be a social networking mogul. (more) 
