[jyl]

On the camera systems - one camera could cover the side door, garage door, and the "alley" between garage and house that is the natural path to the back door. Another camera could cover the front door - I could put it inside, point out through the door glass or the flanking sidelights. And a third could cover the back door. There are power points convenient-ish to all three locations. The cameras supposedly work at night using IR emitters, but I could install motion activated lights at those locations too.

Just browsing, I see systems like these - a 4 camera wireless DVR system costs about $600. A 4 camera wired DVR system is $300-400.
http://www.bhphotovideo.com/bnh/controller/home?O=&sku=984979&gclid=CPzu9OuKn74CFcdefgodn4YAaA&Q=&is=REG&A=details
http://defender-usa.com/product/Sentinel_Wireless_4_CH_500GB_DVR.eng-205.html