David Letterman

America's second favorite late-night talk show host, the gap-toothed Letterman has been getting medium-sized yuks for decades.

Letterman started his career as a radio host and TV weatherman in Indianapolis, but soon turned to comedy writing after managers at the TV station got fed up with his on-air gags. After a few guest spots on the Johnny Carson-era Tonight Show, NBC tapped Letterman to host a morning show called The David Letterman Show. Though it lasted only four months, NBC wasn't dissuaded by the show's cancellation, and gave Letterman his big break in 1982 when Late Night debuted following the Tonight Show. May assumed that Letterman replace Carson when he retired in 1992, but he was passed over for Jay Leno's chin instead, sparking a bitter rivalry between the two late night talkers. In 1993, then-CBS chief Howard Stringer lured Letterman to host Late Night in the 11:30 time slot against Leno. However, he's consistently lower in the ratings. The same year, Letterman set up Worldwide Pants Inc., the production company responsible for such shows as Everybody Loves Raymond and Strangers With Candy: The Movie, starring frequent Letterman guest Amy Sedaris.

Although he gladly hams it up before some 4.3 million viewers nightly, Letterman is guarded about his personal life. He divorced his college sweetheart, Michelle Cook, in the late '70s, and dated Regina Lasko for 23 years before eventually tying the knot in 2009. Both of Letterman's marriages have been populated by highly publicized affairs; affairs specifically with much younger interns and assistants working at Late Night. He and Lasko have one son together, Harry.