Be VERY careful about booby traps and defensive measures, you may be charged with a crime for injuring someone and open yourself to a lawsuit. Most municipalities have laws and/or ordinances against doing something like that. I remember a case in Chicago, where a bar owner was tired of being broken into and he rigged a booby trap. Stopped the criminal but the bar owner was charged with assault (I might be wrong on the specific charges).
You might want to look into a home security system, there are many reputable companies out there. Just make sure they are have a UL certified monitoring center. Contact your homeowners insurance company and find out if they offer a discount for having a alarm system, it helps reduce the cost of the monthly monitoring costs.