About to run cat6 throughout the house, with a minimum of 2 jacks in each room that will have a TV and/or computer. We currently have satellite (I've also run 1 coax to my networking closet for the sat boxes), but might be cutting the cord and going back to OTA (sat coax can easily be moved to an antenna). My question is, should I have a hub for coax connections and run those as well or is it more efficient to just run cat6 and use hdmi to ethernet matrix switches and send the a/v tranmission over cat6?

I'd run it and connect it back to a central location. Coax is cheap, you will already be fishing wire, and who's to say you might want/need it some day or a future owner might want/need it.