Shooting a intruder is effective to defend your self, but not having intruders in your house is a lot better. Shooting also is a repressive action, which requires someone to be there.
So mine first question is very simple, have you though of the preventive measure (target hardening) first? Prevention is usually more effective and is generally considered a better place to start.
You are 100% correct about shooting being a last ditch defense. Like Taurus having had to fire my weapon in the line of duty with (unfortunatly)leathal results, I can tell you there is nothing in my home worth killing for except myself and my family when I'm home. I would allow (during normal times) a person to take anything in my home as long as they left my family alone. Possesions can be replaced, a life cannot.