......BTW, does anyone think it's better to leave some parts of the automation to the wireless?
Motion detectors, fire-alarm's, thermostats for floor heating etc......
I have a load of unused inputs, partly from these ACTinBOX Classic Hybrids
, but also from other various KNX inputs. Potential free inputs work for push buttons (like a door bell) and magnetic reed switches (like door sensors), there are inputs for temperature sensors and movement sensors. I made a decision to go with a standard fire alarm panel for resilience (mains powered, with battery backup) and take a switched relay output from that, to a knx input, to alert the knx/linuxmce system of an alarm condition. Motion detectors I wire to knx inputs. This allows me to perform alarm functions in linuxmce via knx (theoretically, I've not done it yet). Heating I actually have on a separate system controlled by a Heatmiser unit (see discussion elsehwere here) so my HA control of that will be knx->Linuxmce->Heatmiser - but there is no reason you can't do it all in knx. There are knx heating control units, and the InZennio z38's I mentioned have thermostats and control modules for HVAC. In this case you would need at least one in each heating zone. I intend to use these for the upstairs radiators (knx valves on the radiators, z38's as the thermostat control) and the contrived heatmiser scheme for the downstairs underfloor heating.
I like subsystems that work independently, so if the linuxmce box goes down my house still works. I don't mind so much about security alarm, but I wouldn't trust basic house functionality or fire alarm. so for me the HA/Linuxmce control is a layer on top of resilient systems, not a required component of it.