FWIW, the wife and I have an appleTV and an HD TiVo. Just this week we made the decision to dump cable, get an OTA antenna, and save some serious cash.
Why? The only shows we really love are available over the air. We generally watch some trash off the cable channels, but that's really a waste of time we should spend reading or sleeping.
If there is something we really need to watch that we can't get OTA, we can do it on our laptops. On that point, I'd like the appleTV to be able to stream content from the internet. As others have pointed out, Boxee can do that. I'd like a solution from Apple on that front.
No biggie, though. HD movie rentals and airTunes are what got me to buy it, one year ago this Saturday (it was a "valentine's gift" for the Mrs.)
We have just done the same. We were paying $85/month for DirectTV and got an email saying it was going up. I already was using a MacMini for most TV so it seemd absolutely silly to keep being ripped off.
I puchased the Samsung Blue-Ray DVD with Netflix streaming ($9/month) and just ordered an Apple TV. Like you I am planning on a OTA and possibly a HD Tivo as they would also do content streaming from Netflix etc.
I would like to see a better merge of the MacMini an Apple Tv. Having to convert files through iSquint is a pain.