Home Security for a Secure Family Home

I currently rent the place I am living in, and it does not have any type of home security systems. This concerns me some since when the chips are down some people do drastic things such as breaking into homes stealing things. Now while I do not have a lot of things, what I do have I would like to keep, and having a home security system would definitely help protect those things that I want to keep most precious to me, which is my wife and son. The other things can be replaced, but they could never be replaced, and that is what I would most want to protect with a home security system.