I've used ADT - but these are not bought in a store as you have a monitoring service whereby if the alarm goes off they call the police. If you are serious about getting such a service, often times you can get all or part of free equipment and installation if you sign up for their monthly monitoring service each month.
ADT is among the best. (Its the service , not necessarily the equipment that sets everyone apart). Most high tech stuff will be ignored or overcome without a good backup service.
We also have two good doggi
es and a Taurus "Judge" on duty