Chairman and CEO, AT&T
Why he matters: Stephenson hopes to transform a company rooted in yesterday's technology -- telephone landlines -- into a multiplatform provider of telecom services. AT&T's decision to rebrand the Cingular network with Ma Bell's 122-year-old moniker got a big boost with the news that AT&T would become the exclusive carrier of Apple's iPhone.
But Stephenson must also find success with the U-verse -- a long-delayed IP-based television system that will put AT&T in direct competition with cable companies. In May, AT&T announced that it will spend $6.5 billion ($1.4 billion more than previously announced) to roll out the system in 20 cities. If the effort fails, Stephenson could go the way of the rotary dial.