>>I plan on using an antenna and complimenting that with this box running XBMC.<<
Unless I missed something, that box you asked about doesn’t have the ability to watch over the air signals. It would need some hardware inside like this below:
http://hauppauge.com/site/products/data_hvr2250.html
That is the card I have in my HTPC.
Yes you are correct.
I just meant a straight antenna to the TV.