51. Tina Fey

She had already earned a lifetime's worth of awards for producing, writing and starring in "30 Rock" (co-star Alec Baldwin calls her "this generation's Elaine May"). But Fey became a national phenomenon this fall with her dead-on impersonation of Republican vp candidate Sarah Palin on NBC's "Saturday Night Live." The move boosted the show's ratings in September and October some 46% over the previous years and drove millions of viewers to NBC Uni-owned Web sites. Her momentum also led to "30 Rock's" best ratings ever, for its Season 3 premiere (8.5 million viewers). To top it off, she starred in a hit film (Universal's "Baby Mama," more than $60 million domestic) and inked a book deal with Little, Brown & Co. for a reported $5 million advance. "Tina is the zeitgeist woman," notes "30 Rock" producer-director Don Scardino. "In 2008, she became a brand."