Let's think about the constitution in context. It was written 200 years ago, when defending ones home was direly necessary. I don't think we have to worry much about troops invading our homes these days. No one is arguing the constitutionality of owning a gun, its simply time we amend the laws to update them with current society. There is no reason why people should have as many guns as they do.
And as far as Mr. Rapist goes, invest some money in a decent security system. Guns are not the answer. Studies have shown guns stored in homes often are used against ones own family or other innocents. While being Davey Crockett with your gun in your cabin to protect the womenfolk may seem noble, there are other effective ways to keep out those dirty bandits that roam the countryside. Now tell me, are you really worried about some bum breaking into your house, or are you more worried about your precious semi-automatic assault rifle being taken from you?
Perhaps you misunderstood me, I'm not telling you you can't have guns. Just that you don't need a miniature arsenal in your closet. Guns make it easier to kill people, and the more we have, the more available they become. Is it too much to ask that there be limits set on who can buy guns and how many?