The films: The Good Shepherd is a quiet epic of espionage both international and personal. Casino Royale is a flashy epic of espionage both international and personal.
The actors: Damon, one of the gravest and most charismatic actors of his generation, and Craig, who is joining him in that field.
The characters: Men of steel. Edward Wilson and James Bond. Tough as nails. All business. These aren't "performance" roles. These characters require reserve and control. They require actors whose mere presence can turn one note into a symphony. Wilson and Bond each betray one smile in their films, and Damon and Craig make these instances well worth the ride of stoicism.
The moments: For Damon, it's the film's opening sequence, when his gait and deameanor -- the way he carries his briefcase, and his shoulders -- convey Wilson's entire history of repression. For Craig, it's the torture scene. It must be hard as hell to act a torture scene, and even harder to be an irrepressible prick during it.