Pat,
Don't wast a lot of money on an NTSC tuner box when you already have one built into your set. Also keep in mind that the Antenna is only for "over the air" local channels. Cable or satelite can be routed through the receiver. Buying another box would also require using another remote.
I would recommend investing your money in a good URC or Harmony universal remote. When you press the "TV" macro it will change the TV input and receiver input at the same time. Once setup, it will be easy for the whole family to use the system.