Run at least stereo speaker wire to each room, looped through volume control/keypad location. Run cat5e/6 to volume control/keypad location.
You might want to run surround sound speaker wire (so six speaker cables or more) to some rooms from central location (I did that for my living room).
Run at least two cat5e/cat6 cables to each room, can be used for ethernet, hdmi, IR, audio, whtever.
Run at least four cat5e/cat6 cables to each TV location. Maybe coax too (I didn't but I live in an apartment and won't get satellite or such).
You'll never regret running "too many" cables. Too few though...