I just joined in:
One major problem with having a gun in your house is that if you do use it to shoot and kill an intruder, do you really expect that the legal system will simply say 'okay, he did it in self-defense' and let you go off? I seriously doubt it, I would expect a major court battle with plenty of expenses and stress. Especially if the intruder is unarmed (many experienced burgler know better than to arm themselves because that turns their crime into armed robbery if they are caught). Remember, the legal system does blow!
Plus, killing someone is not something to be taken lightly, in most cases, it does come with it's own load of stress--no matter how tough you think you are (most soldiers are pretty tough to me, and they experience a lot of stress from having to kill people). De-humanizing the criminal and satisfying a desire for revenge may not make things better either.