Always have a couple of pistols handy to use in an emergency and can also be used to fight your way to some better “hardware”.
http://loadoutroom.com/7121/shocking-facts-gun-fights/
That is a good video with shooting suggestions and scientific facts of how fast a person can move toward you and how fast you can pick up the gun and fire.
I also liked that video I saw on the thread about ending up the winner when someone breaks into your house. The first rule was don't go where the bad guy is when in your house - make him come to you and enter your target field - then kill him before he sees you.
In television/movies, the home owner invariably leaves the room, usually the bedroom, and searches for the entered bad guy - never do that as you enter his kill zone - make him come to YOUR kill zone.