My own thoughts:
* Simple bell types end up being little more than an annoyance to neighbours. A dummy alarm might be better.
* Monitored types come with regular payment costs. Police are unlikely to have the capacity to investigate every time they go off.
But with modern technology there are surely some better options, notably:
* Rather than the alarm annoying neighbours or the police the alarm could silently send a text to a few mobile phone numbers when it is triggered and/or via broadband.
* Images could be made available via broadband to a phone app. Something using open standards would be better than a closed, proprietary system.
* Rather than running wires around the house, detectors (open/closed and motion) could wirelessly send to the base unit, though to be practical their batteries would need to last for a long time, and have an LED to indicate state.
Any corrections to my ideas? Any suggestions for a system that will do the kind of thing that I have in mind?