No smart as$ answers necessary.
What state do you live in? Look at Castle laws for your particular state.
Too many effin psychotics in America for too many reasons. Mental insanity, job loss, poverty, crime of opportunity, tough economy, you name it. I don't give a sheet what reasons someone has. They have NO right to break into my home with the intent of stealing from me, hurting/killing me, and/or my hurting/killing/raping my wife.
I've been raised by a responsible father who taught me to use both his handgun (a Ruger) and his shotgun (Remington). I'm comfortable with guns. Currently looking for a personal protection weapon (leaning towards Airline pilot discounts deals with H&K Compact LEM and Kahr weapons). My wife has never used a gun, but I will teach her responsibly. Learn, and learn it well.
And for those you naysayers who think this will will never happen to you, please wake up. Look in past history with mass shooting sprees. Virginia Tech shooter. The Amish school shoooter in Pennsylvania, the Omaha mall shooting, Columbine, etc. etc. etc. You know what all of them had in common? The rampage ended only, and ONLY when the gunman decided to turn the gun on himself. No police shot any of these mass murderers. By the time police get there and attempt a rescue attempt, it is already too late.
....don't let it be too late for you. Be responsible, be safe.