Shotguns are great if you know they're breaking in,
once they're in, I'd give thought to a dependable
pistol, like a CZ75, Beretta 92, 1911A1, or S&W
revolver...
If your state doesn't have Castle Doctrine, the cops expect you to
run into the bushes outside your back door and hide.
Bring your phone, because then you'll just have to call the
justice system which
disarmed you in the first place, and beg them to get your
house back for you. It might take a few hours, (or days) but
what the hell, that's what you're paying a mortgage for,
isn't it?