I think there are many good, valid approaches to home security, but let me give you mine. It has worked well. I went through the process about 5 years ago of trying to decide how to secure my home. I had a vested interest in something that really made a difference as I was deploying (military Reservist being sent over seas for a year) and leaving my wife and two kids behind. I looked at all the options including commercial, etc. We had good neighbors (this makes a HUGE difference) who helped look out for the place, as well. I ended up doing two things. First, a dog. A very big, very friendly dog. The kids could have bit his ear off and he'd of just rolled his eyes. Stranger comes to the door and he goes all Jekyll and Hyde. Second, IP cameras. Lots of them. The cameras covered inside and outside. I ran the whole show with EvoCam (from Evological) on a Mac. No, it's not open source, but it is only $25 and it's absolutely awesome software that includes customizable motion sensing (with exclusions), triggers, alerts, uploads, recording, remote view, etc. By doing this, I gave my wife the ability to secure the house while she was home using one template, while using another when she was gone. Her big concern was coming home to an empty house at night. Problem solved. She would receive alerts on her phone (with snapshots) if there was so much as a car that turned around in the driveway (or a the neighborhood fox ran through the yard). She even got to where she used it to figure out how the dog was getting into the pantry. The camera/software setup really took the place of a commercial alarm system and aside from the initial cost (Axis cameras aren't cheap, but they're very high quality) it was a very reasonably priced solution.