Shotgun loading for Home Defense?

Right now i keep my 12 ga loaded with 3 heavy game (says its for rabbits, etc) shells followed by 2 slugs. Do you think this is straight, or i should use all game loads? I live in a townhouse and i know slugs get nasty and tear through walls (brick home though) but i ume i'll probably not get that far down the magazine tube(or whatever its called) and if i do, then i'll want a KO. What is the best way to handle this?