150lbs of Doberman is my early warning device (two dogs), loud toothy and fairly protective. After that it is either a .45 (I like flying ashtrays) or the trusty .357 mag.
I was told the same thing as SeaStrike by the officer responding to my break in call(neither the Dobies or I were home during the incident). Dead men tell no tales .. (and they can't hire attorneys) .. .
I also learned the same theory as DogFish, keep firing until the weapon is empty or the threat is neutralized/down/dead/no longer a threat.

Salmo, another portion of the shotgun as best home defense weapon is that if fired, wether you hit the target or not the assailant will be scared sh!tless, mostly deaf and blind and easy to track by the smell they will be emitting from their drawers as they flee the scene . . .