Cutting the cable, lets talk options and media setups

St. Ouachita, thank you thank you!! I have a nice 27" iMac and would love to incorporate it in my setup, love the idea of AirPlay which I need to look into more.

Question for antenna users, does the coax from the antenna just plug right into the antenna jack on my TV, is that gonna be HDTV signal?? All I'm reading is that coax is the worst type of signal connection. How do you connect to the HD signal from an outdoor antenna?