Jack Bauer (Kiefer Sutherland, 24: Live Another Day)

"I've spent a third of my career playing Jack Bauer," Kiefer Sutherland says on the London set of 24: Live Another Day. Heading into the show's 200th episode, the actor remains fully invested. "Jack is heroic for the reasons he's always been — he's completely committed, he's got enormous integrity and he still slams through windows and doors to protect what he believes in." And he's had plenty to contend with recently: a goth Chloe (Mary Lynn Rajskub), the return of ex Audrey (Kim Raver), the exposure of CIA honcho Steve Navarro (Benjamin Bratt) as a mole and a new terrorist mastermind (Michelle Fairley). The final four episodes will be just as challenging for Jack, Sutherland says. "We left Season 8 open-ended. Now we're going for closure. And let me tell you, it ain't gonna be tied up with a bow."