Ethernet everywhere, and more than you think you need, even if you don't terminate every connection. Put in Cat-6, as it's easier to pull, and future proof. Everywhere you think you might need one cable, put 2, need 2, put 4. In fact, 4 strands/room might not be overkill. Where everything comes back to, put a patch panel - you can buy panels with 24 square slots and a bracket to hook it into the wall. I'd put this in…
On house time scale, not sure Ethernet is future-proof, might want to run fiber or who knows what in 20 years. Twisted pair is only mass market for last 20 years.
Or you might even want to run speaker wire or who knows what.