In better homes? That's kind of a relative term..
I'm currently home running cat5e for telephone and networking along with RG6 per bedroom, kitchen, living room and den.
That's just the standard.
I meet with the clients and work on upsales to keystone plates (easier for me), whole home audio, home theatre wiring, conduits from basement to attic, conduits around fireplaces for plasma mounts, etc..
Most standard production builders just do cat3 looped around the house for 2x phone, home run RG6 for 2x cable, and no network.
What I recommend is 2x cat5e on RJ45s along with an RG6 run to an F81. Bundle all of these into a single keyplate.
Terminate all the cat5e to a patch panel inside a metal box in the basement. This allows the HO to patch each jack around the house to either a telephone bus or a network switch.
http://www.phonejacks.ca/networked.html
