I had asked around to some friends in KY about what they do there (because people in KY tend to be real cheap).
About the cheapest installation is to use a webcam and some low cost software with an old obsolete Windows PC-- about 50-60 bucks for a single cam "DVR" plus the scrap PC.
With broadband and a smartphone, it can also send EMSG w/pix or vid to the smartphone when triggered, or periodically. Using a slightly more expensive PTZ wireless cam like one made by Foscam (about 80), remote pan/tilt can be mechanized (at least on Android, not sure about iOS).
Using cloud storage, the perps can't even steal the video anymore... and if the cloud is outside your country, the police can't get to it either (at least not easily) [this is for you paranoid conspiracy theorists].
Finally, cameras can't be everywhere outside-- there are always blind spots, or spots where the image isn't good enough. But, ARDrone can be most places (this is basically an RPV with a camera, it is a toy and not very practical yet for this application, but in a few years and some built in stabilization algorithms an iARDrone would be ideal for launch and quick surveillance in blind spots or to auto track a vehicle for a closer look. If the perp tries to skeet it out, he is probably going to be toast on multiple offenses more serious than trespassing)