if somone breaks into your house for whatever reason, be it burglars or even just some drunk whos found his way in off the street, when they see you they no longer want to be in the house.
if they see you and you are in a defensive mode (for example you are shouting at them or have a stick or something) they really are going to want to get out as fast as they can.

a burglar is not a murderer so i dont think having knives and other potentially lethal weapons is neccesary, as long as you have something thats going to make him think twice about coming in your house.

as for your suggested weapons there are some pretty good ideas there! id be suprised if some bright spark hasnt written a book of improvised weapons yet!

pens are a good one, used like a kubaton gripped in a fist.
anything for that matter thats hard and you can throw at him

good topic btw!