How do I wirelessly stream my movies to my projector?
The streaming of music and video to Apple TV is quite remarkable in my book. Having Safari on the iPad, iPhone seeing the AppleTV as a target for many video types is still like magic to me.

Not everything streams, but if it's HTML5 video or something you don't mind placing under iTunes's purview - it's a great solution. As AirPlay gets more prevalent, the web sites that will allow this should grow over time. With media you control, it's ready to go with perhaps a re-encode if it's not something the Apple TV expects to play out of the gate.