I'm very happy with my EyeTV Hybrid and its software. I get a decent selection of HD channels over my rabbit ears, and with analog TV on the way out, more digital broadcasts should become available. All free

And commercial free, since I watch later and skip them. Hulu and the TV network sites provide other free programming, including cable shows like Battlestar Galactica, so there's no need for me to pay for cable.
Note: the choice of antennas matters. A big wall-mount or roof antenna will likely get more channels than indoor rabbit ears, but also one brand or model of antenna will do better than another. I read that the
Philips Silver Sensor PHDTV3 was the best indoor rabbit ear choice, and sure enough, it seems to be true. NOT the earlier Silver Sensor with a tall black stand, but the low triangle with rabbit ears attached (look at the picture). I first bought some other name brand HDTV antenna and didn't get many channels. Then I bought this one. (Note that you don't NEED special rabbit ears for HD, you can use any old rabbit ears--but they won't work as well if the signal's not strong. If you already have a roof antenna though, even if it's not "meant" for digital it may be fine.)
Also, if your signal is weak, a few degrees of rotation or a few inches of movement can make the difference between no picture and a clear picture. This site (I think this is the one) can help you know the directions to try aiming:
http://www.antennaweb.org/
I aim generally toward the largest number of stations, but I get others I'm not aimed at as well. And every few weeks it seems I have to adjust my antenna--maybe weather-related.