You don't even need an AppleTV. My Roku and Amazon TVs were both zero-configuration AirPlay targets. And generally speaking, there's not any issue with wifi streaming video - there's a noticeable input lag, but it doesn't desync audio, and videos tend not to be interactive.
Yup. I'm introducing my sister to the masterpiece that is Chrono Trigger by playing an emulated version on my Mac streamed to our Roku TV. Works great. Video is even easier.
