I've always said, if you're going to shoot someone, make sure they're dead. No shooting kneecaps (you won't hit them anyways), no shooting to scare them. If you shoot them, make sure they aren't around to tell their twisted side of the story.
But, as LJ said, 'neutralize' is a much better choice of word. Sounds better when you're in front of a jury.
BTW, don't empty the 'clip' unless that's what it takes to stop them. 2 to the chest should slow them down enough to put a well placed/aimed shot to their head. If that doesn't work, reassess the situation and repeat as necessary.