I pull content from my iTunes library with multiple Apple TVs.
EyeTV sits on my office computer, pulls in TV Shows, records and transcodes them to iTunes. I have a script or two that tag the files and send me an email when they're ready to view.
As far as changing channels and such, I use an OTA ATSC antenna mounted in my attic. All TVs are fed with that signal in addition to having AppleTVs, so if I want to channel surf the limited cable selection that I have I simply tune with the TV tuner.
Most of my viewing is of Netflix streaming or EyeTv recordings. We rarely watch live tv, other than local news.