The video watched on an ATV is not live viewing for the most part. It is made to watch downloaded files from the net or ripped off DVD's. Boxee will allow you to watch streaming video similar to the way YouTube works. I'm not sure if you can still access Hulu using Boxee any more, for some reason Hulu does not like it when they do. Even then Hulu is not streaming live video. You should go into the iTunes Store for your country to see what programing they have to offer for download as well.
Apple TV gives you access to the best 1080p HD content right on your widescreen TV and it is a digital media receiver developed and sold by Apple Inc. It is a small form factor network appliance designed to play digital content from the iTunes.
No. The Apple TV is not designed to be a cable box, satellite box, or over-the-air receiver. Google has attempted this with Google TV but it is a complete failure. Apple is intent on delivering content on a subscription or pay to play basis. The unit would have to be much larger in order to incorporate a cable card (to receive cable TV), the extra circuitry needed for a satellite (along with an authentication card), and the extras needed in order to process over-the-air content. Given the fact that digital over-the-air receivers have been built into TVs since 2004, there really is no point for this.
The Apple TV needs to be updated to run apps first and foremost. That would open it up to more possibilities than acting like a TV receiver.
The closest you will get for now is using apps on an iOS device to AirPlay the video to the ATV for viewing on a TV. Here in Canada, and most other countries I suspect, we have limited video in the apps provided by the networks. Mainstream TV video apps are a little better in the US.