Adam Baldwin as Kal-Reegar

You know him as: The Man They Call Jayne (Firefly), Colonel Casey (Chuck), Animal Mother (Full Metal Jacket)

Like Baldwin's other roles, the quarian Kal-Reegar turns out to be more than just a guy with a big gun (though that's another thing Jayne, Casey, Animal and Reegar all have in common). As Reegar proves at Tali's trial in ME 2, he's got a brain between those ears. Unlike real-life Adam Baldwin, who by most accounts (and his own Twitter feed) seems to be pretty nuts. Don't get us wrong—we love watching him shoot at shit. We're just a little scared of him.