Comcast's Brian Roberts: The low-key exec who leads a high-profile giant

Comcast (CMCSA) CEO Brian Roberts celebrated his 50th birthday in June by competing in and finishing the Philadelphia Triathlon along with a few top lieutenants. That may be good training for the task at hand.

Roberts, 50, who announced a deal on Thursday to gain control of NBC Universal from General Electric (GE,) may become one of the most powerful media titans in U.S. history, but he's decidedly low-key. Unlike his flashier counterparts in Hollywood, Roberts (pictured, left) doesn't crave the spotlight, and sources say many Comcast employees consider him to be a nice guy (but it's easy find outsiders who have less favorable views).