I'd get at least two (if not 4) ethernet cables run to every room you might have a use for an internet connected device, even if that's only a future possibility of a device.
If you are getting the whole thing redecorated (which I assume you are, given the thread in the Home & Garden section), I'd also get some cables run to the ceiling, somewhere around the middle of each floor (ground, first, second possibly?) where you can put a ceiling mount Wireless Access Point.
This way you should get decent WiFi signal around the whole house, and you'll have the option to cable up should you need/want to.
Get all the cables run back to a central point, somewhere near the master socket (if you are using FTTC/P, otherwise to wherever your WAN connection enters the building if you are using VM or similar), and terminate them on a decent patch panel. Couple that with a decent 16-24 port Gigabit Switch and you'll be golden.