I recently purchased an AirTv device. Its android based, can be hooked up to the internet via wifi or ethernet cable, and has an adapter allowing the connection of an antenna. What it does is includes the over the air channels in the same menu as the SlingTV channels. I really like it, the only downsides are that you aren't able to surf through channels to see whats on (you're limited to the guide menu only) and it freezes up / fails to load shows every once in awhile. Otherwise it saves me more than $50 every month.
As for antennas, I have the Terk Trinity. I have it on the fourth floor of an 18 story building in a downtown area and I'm getting 30+ channels.