my security is sensors on the areas around my house nobody should be walking around,keys never left downstairs,house is alarmed to the hilt,the area where someone could get in is deadbolted so no one if they did amongst the alarm inside and outside the house making their eardrums bleed could not access upstairs also a camera for viewing areas without leaving the house.
oh and a big bat just incase which would mean the crap has hit the fan as violence is not my thing but as needs must it can be.
also a viper alarm/pager with proximity and shock sensors on the car.