Yikes! That's a good reason to look into a solution. I've had good results so far with z-wave, although I've only just broken into the area myself.
The products are cheap, effective and reliable so far as I've seen and read. The MiCasa Vera controller is probably the best for most people ($100), then at least one $30 motion sensor at minimum, but I currently use the InControl solution (usb stick with an old laptop that always stays on) since it's slightly cheaper, and the mobile app is more visually appealing. I also am buying all kinds of sensors simply because I think they are interesting, as well as convenient (door/window sensors for $35, multi-sensors [temp, humidity, motion, light] for $40, energy meter that tells me how much energy my entire house is using every 5 seconds for $50.)
It's also worth noting that Wireless IP cameras can be purchased for as little as 30 dollars each off amazon. http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=ip+camera&rh=i%3Aaps%2Ck%3Aip+camera
You don't need a system for those, just a free, or very cheap mobile phone app, and a wireless router (plus some time to set them up).
The more you spend, the less difficult it'll be to set things up from what I've seen. I always go with the cheap stuff, though, as I don't mind the challenge.
The canary is the best solution I've seen for an expensive, but VERY simple, yet useful solution. It's coming out soon: http://canary.is/