Definitely Sev, from Star Wars Republic Commando. He brought kickass into Star Wars.
Quotes:
Fi: But you get to wear face camo instead. Makes you feel wild and dangerous.
Sev: I'm wild. And then I get dangerous. Shut up.
Fi: Miserable di'kut.
Scorch: Don't mind him. He'll be fine once he's killed something.
Sev: Damn! I don't believe it!
Scorch: What's wrong, Sev?
Sev: I lost count of my kills!
Boss: We're headed up to the top, squad. Be prepared for anything.
Scorch: I'll take up any day. Down's always been bad for me.
Fixer: Do you ever stop talking, Six-Two?
Sev: Up, down, what's the difference? As long as we live and they die.