Shotgun or handgun for home defense?
The answer is both, but each for its own application. (there is a reason why a tool box has more than one tool in it)
(h/t http://tslrf.blogspot.com)
Chris Costa is the president of MagPul and is a former member of the Coast Guard. Normally, those qualifications don't mean much in and of themselves, but in this case I agree with his advice.