To address Amir's question more succinctly, I believe there are two distinct ways to handle the "bad guy at the door". For purposes of this immediate post, we'll assume that he has NOT committed forcible entry into your home (yet).
1. Count on your exterior fortifications and cell phone communications to slow his entry (if a forcible entry is being attempted) while summoning police assistance. Consider escape routes for your family from the anticipated points of entry in your home. Consider the "safe room" concept, as far as you might be willing to take it.
2. Have some type of deadly force weapon available and have some training in how to use it effectively. Apply your training to your home environment, so that you may understand the amount of space, etc. in which you might engage a hostile subject. Consider what you would instruct your family to do (and where to go, etc.) if you were to confront an intruder in this manner. A good flashlight is an excellent tool, since many of these scenarios play out in low-light environments. There are convenient flashlights that have dedicated mounting systems to attach to your firearm, or you should practice with single-handed use of your flashlight while wielding the baseball bat, etc. with the other hand. THINK about what would actually happen and what you would be required to do! Also, have a basic understanding of the "castle doctrine" laws in your state, which govern the use of deadly force in protecting your home from intruders.
I don't advocate "bluffing", as criminals have become more attuned to the behavioral aspects of victims (whether armed or not) and they understand that a weapon presented but not used is less likely to be used as time progresses. So, either be ready to retreat to safety or to be prepared to offer a higher force level in return. Once you've made your decision about which path you want, then planning the most effective methods and tactics is more straightforward.
rrr's suggestion on Ayoob's book is excellent.
Lee