In our show room, we have an LCD TV with built-in
HD tuner. So I used a small antenna like this one that came with the Dish Network receiver:
And believe it or not I am getting all the local HDTV channels with it.
However, we are not that far away from the towers, so the signal is strong.
For a stronger antenna, I would recommend looking at #1 or 2 here:
TV OFF-Air (OTA) Antennas GE Winegard DBS Active