I really don't understand all the comments about why doesn't it have a DVD player, or it doesn't have Tivo capabilities, ect. I really think you all are missing the point: it is designed to eventually replace all those technologies. OK, it doesnt' do it yet, but Jobs said something very important at the end of the keynote, and that was "you can see the direction we are heading".
The whole concept here is to make DVD players, recorders, rentals, and even channel viewing irrelevant. You will purchase, subscribe, rent?, and control all media content on your computer and simply stream it to an HDTV.
Does it support HDTV resolutions? Not yet, but I'm sure it will. Remember, iTV is a direction, not the end of the road.
So, the complaints are more or less becaues we are impatient and want it all now. This is just a start. If done right, this concept of computer, iTunes Store, and iTV could replace cable and satellite TV service. Why screw around trying to record shows, edit commercials, ect. when you can just get and control your content easily and simply with your computer?
I like this whole idea. I can see cable news channels offering their content via TVcasts that you can subscribe too, and other network channels offering their media libraries for download or even rental; and the iTunes Store will basically act as the purchasing hub. Want Monday nights football game? Just subscribe to it on iTunes and it will download automatically and you can watch it whenever. Who needs Tivo? Don't need 200 channels of crap? Just download the stuff you want to watch and have your own media library. Who needs cable and commercials?