I like the IP cameras out there, as they can be used on an existing network and selected via their IP addresses. Yet, running Ethernet to exterior locations would be tedious in this house, but on the other hand would be convenient since they can use PoE to get their power (rather than trying to run a separate power cord to each one). I don't like the wireless cameras--it won't be long before even the dumbest of criminals learn they could foil any wireless camera with a common signal jammer. I would want something with PTZ (pan/tilt/zoom) that I could adjust remotely, and/or set to "patrol" mode to do so automatically. It would also need infrared to see things at night, and have high enough resolution to enhance detail. An acquaintance of mine is a VP at a company that designs and sells surveillance hardware and software. I have always meant to ask what he would recommend as a reliable and affordable setup for a home.
For now I have installed a couple of inexpensive motion detection security lights outdoors. LED, so I'm not so concerned with power usage or bulbs burning out. I still want to install cameras, though.