I stuck with BananaTV for a while, because it was more reliable, but AirServer 3 is rock solid. I run it on my home theater Mac Mini, so it works just like an AppleTV. Sweet!
Now, with the Media Center Safari Extension, I can be surfing, find an interesting video on YouTube, Vimeo etc., and with a click, put it up on the big screen to share.
What I don't get is, why doesn't Apple bake this functionality right into Safari/QTPlug/QTPlayer/iTunes? They tout the technology, but don't give you even basic tools to use it on OS X, whereas you can send *any* media from your iPhone/iPad to an AirPlay device. Doesn't make sense.