To rburch and everyone else who carries a weapon:
What you wear does make a difference from witnesses, the officers who first respond, investigators, the prosecution and the media who demonizes you, the lawyers who will try to rape your wallet (and that is just your defense team) to the judge, jury and civil trial all over again.
What you carry for a weapon makes a difference as does the brand of ammo.
What you say before, during and after the shooting makes a difference.
My advice is to be the "gray man" as mentioned by steppenwolf. Even though that is not my style. I'm a LEO, even if I dressed like a gray man I would telegraph my "copness" to bad guys. (It's in my B.O. I guess
) So I dress the part so my brothers and sisters in blue, brown, or khaki recognize me as one of the fraternity and the bad guys get nervous when I give them the stare.
My advice on carrying a weapon is to pick a solid dependable factory pistol and don't customize it beyond adding night sights and grips. Threaded barrels, porting, lasers, etc. can work against you. Unless you are part of an entry team don't carry a tactical pistol. Save it for competition, the range, or the PAW.
My advice on what you say is to be polite, avoid arguments, give verbal warnings/commands without swearing or name calling and ask for an attorney after giving a very, very brief summary of what happened to the first responding officers. Such as "this guy came at me with a knife. I backed away yelling for him to drop the knife. I yelled (X) times before he forced me to shoot him. He kept on coming at me so I had to fire until he stopped his attack. Then I called 911 (or had someone else call 911). I want a lawyer."
To Paladin1 and Absintheur, that's fine that you wear the gear but be vigilant because you are advertising. It's likely that most street cops will count you as among the good guys (unless you are in a gun hating city
) but it won't help in court. But then again, there is very little that will help you in court except getting the best lawyer and self-defense expert witnesses to counter the BS the other side is going to sling at you.