I saw this link that John Gruber posted about a recent report on the habits of Apple TV owners and, at the end of it, he mentions how some of his Twitter followers use the Apple TV. He says:
"And lots of DF readers on Twitter[are telling me](https://twitter.com/#!/search/gruber apple tv)they use Apple TV just for AirPlay and Netflix streaming."
That is exactly what I use the Apple TV for. I do not buy or rent TV shows or movies from the iTunes store. Ever. Although the Apple TV integrates with the iTunes Store, Home sharing (for sharing files from a computer), the NBA and MLB (and others), Vimeo, YouTube, Flickr, etc. etc. the two features I use on my Apple TV are Netflix with Airplay.
I use Airplay to put videos I find via my iPad on the TV. I do this a lot. (Thanks Devour) Even if the source of these videos is from YouTube, Vimeo, Viddler, and other outlets - the integration with any of those platforms goes unused by me since I simply use Airplay. I suppose if I didn't own an iPad my use of Airplay wouldn't be nearly as significant. It is just so easy. I'll also, on occasion, use Airplay to play some music via my Apple TV (this replaced my Airport Express' purpose) and very, very rarely put some vacation photos on-screen.
Another note about Airplay; if you, like me (and obviously Jason Kottke), sometimes acquire a few TV shows you couldn't get otherwise by grabbing them via Bittorrent you may be interested in Erica Sadun's Airflick. Airflick is an application that lets you stream video, audio, or photos from your Mac to your Apple TV. Very handy application.
But all-in-all my Apple TV might as well just be a Netflix box. I've used Netflix on the computer, on an Xbox 360, on iPad and iPhone and on Apple TV. By far the very best Netflix application exists on the Apple TV. It is easy to use, looks great, and works nearly every single time without hiccup. I don't know if I'd even be subscribed to Netflix if I didn't own an Apple TV.