I recommend a 12-guage pump-action shotgun, with a shorter barrel (~19 inches) and a real stock (not a pistol-grip).
For home-defense, I believe a shotgun is better than a handgun for the following reasons:
a) The shotgun's spray pattern is more likely to hit your target than a conventional round, especially considering you will likely be firing in the dark and under fearful/stressed conditions.
b) A conventional round would be more likely to penetrate walls, possibly injuring family members or neighbors.
c) Nothing beats the pure intimidation factor of the sound of a shotgun's pump action.
Of course, an even better solution may be to move somewhere else, where you don't have to worry about home-defense as much.
Guns are bad juju.
good luck, R