[Phalanx]

As long as they're aware of that risk in keeping one...I think if one IS kept in a responsible way, you'd be at less risk. I say the first measure is a decent alarm and security system, if that goes off and somebody persists, you'd be alerted to their presence in good time to fetch arms. I really couldn't see somebody getting through that, and taking a person unawares in their own house and dissarming them. I mean...if they COULD, then I probably wouldn't suggest that person owns a firearm in the first place.
I think the motto "don't take it out unless you're ready to use it" (hm...that works a few ways) is a good one...I really can't imagine if someone were ready to use a firearm and properly prepared, could not come out on top...getting shot with your own gun...I have to say that there's the mark of someone who could use a little more training (which I believe is part of responsible firearm ownership also)
I say if you're gonna bear arms, be prepared for the consequences, and potential risks involved. Of course, it's a risk that I think is worth taking if it meant the difference between being able to protect your family from multiple unarmed/non projectile weapon weilding assailants, and not.