In a home defense situation and the range at which you have to make the shot all I need is a .45 acp with standard ball ammo. It worked all the way through WW2.
A stack of 6 soft cover books will stop a .45 acp so over penatration which is a concern is minimal. The .45 was specifically designed to kill scumbags and it works VERY well at distances inside a house.
The other benefit? You're not trying to swing a long barrel around in a hallway or banging it on various appliances whilst in a state of fear, panic or whatever may be the case at the time.
For me it's a handgun in the house and a .45. Unless your being assaulted by the government or local gang members which most of us don't have to worry about. At least for right now. In either of those cases you're probably going to be outnumbered or outgunned.
