I would go for screened CAT 5/6 in every room if you can ; routed to a switch and base station in your utility room. That way you can power things like radiator valves and CO2 and PIR sensors remotely, without having to have unsightly AC wall power supplies feeding everything. If you are going to run in cable, it makes sense to have the facility for power supply as well. If you do run in fibre instead, every device will need a data modem to feed the fibre which will need power, so run in power supply cable with it. I would run CAT 5/6 to every room and maybe a fibre to your main television viewing and listening area(s).
Using Wii-Fi is not as reliable as copper and means having to have security and passwords and brings the possibility of remote hacking. A test conducted by Which magazine who equipped a house with cameras and all sorts of consumer Wi-Fi connected devices, received 12,000 hacking attempts in the first week. You don't want the possibility of criminals being able to eavesdrop or view your children or home remotely, or detect if the house is unoccupied.