Well, I always like Scorch and Sev's rules from Republic Commando. They never made a complete set, but these are the ones we know of.
Rule 1: Kill 'em before they kill you.
Rule 17: Always make sure they're dead.
Rule 23: Never pull sentry duty on an empty stomach.
Rule 39: Never say no to bacta.
Rule 45: Any crash you can walk away from is a good one.
Rule 89: One's an anomaly, two's a trend.
Some of their other quotes are awesome as well:
Scorch: If we're all clones, why am I the only one with a sense of humor?
Sev: A well-built sniper rifle is a beautiful thing. Ours has two zoom modes, "Up close and personal" and "Hello, you're dead."
Boss: [dying, while the squad is under fire] Need bacta... commandos...
Scorch: Can you die later, sir? It just isn't a good time now.
Boss: Cancel that bacta, Commando.
Scorch: Sadist.
Boss: Cancel that maneuver, Delta.
Scorch: Are you trying to baffle the enemy into submission, sir?
Boss: Cancel that demolition, Delta.
Scorch: You're no fun anymore, sir.
[if the player accidentally blows himself up]
Scorch: And that's why explosives needs special training.
Scorch: Uhh, Sir? Do you want a light boom or an explosive party?
Boss: Just get us in without getting the squad killed Scorch
Scorch: [during splice] No terminal is a match for my 'Leet haxor skills!