You can't underestimate Tina Fey's significance as a Saturday Night Live cast member, the first female head writer and one of the top three best "Weekend Update" anchors in the show's history. Sure, she was never the sort of SNL-er to do goofy characters or a myriad of impressions — a fact she points out during her monologue when she hosted the season premiere last year. But the 30 Rock star is responsible for a lot of the high points of her nine-year tenure (1999-2006), and Fey's hosting gigs brim with the sort of smart, biting wit we associate with her reign. Case in point: That incredible Girls parody, which simply would not be as laugh-out-loud brilliant without her playing the confused new best friend Blerta. Simply genius.