Formerly the president of digital media and market development at NBC Universal, Comstock is now a senior vice president and the chief marketing officer at NBCU's parent, GE.

After graduating from The College of William and Mary, she landed an on-air gig covering the legislature for a regional news service in her native Virginia. When she realized she didn't have the skills to be a TV star, she moved over to the business side and took a series of corporate communications jobs at CBS and Turner. In 1993 she arrived at NBC in New York and was soon named vice president of communications at NBC News. Five years later, Jack Welch moved her up to corporate to serve as GE's veep of corporate communications. She was later upped to chief marketing officer, in which role she tried to update the company's image, replacing the long running catchphrase "We Bring Good Things to Life" with "Imagination at Work." In late 2005, she was dispatched to NBC and placed in charge of the digital media division, where she had the unenviable task of sorting out the future of digital media. She retreated back to GE's comfy confines in 2008.

Comstock has a rep as a brutally demanding boss and exceedingly tough negotiator. "She's lethal. She could take out your kidney, and you wouldn't know it was gone," a colleague told a reporter shortly after her arrival at NBC. She's not just tough on her underlings, either. When Comstock first joined GE, she was so abrupt on the phone with her colleagues that her boss, Jack Welch, repeatedly crank called her to get the point across. [Image via Getty]