My PC is hooked to my HDTV, and I am sure alot of others have done the same. I really do not see any reason why I would every need to use a game box or a blu-ray player to stream a netflix movie. The PC does just fine for streaming netflix movies and it rivals my stand alone Denon blu-ray player with its .mkv/x264 file playback capabilty.
I would be interested in the streaming bitrate they intend to use. Anything near HD quality is going to require some horrendous bitrates. If everyone with an xbox or blu-ray player decides that streaming HD is the bomb, I think we all have a lot more to worry about than stupid ISP caps. Something more along the line of ISP collapsing due to congestion would be my guess.

That assumes that netflix even has a big enough pipe to deliver the bandwidth demand that may come from this, I suspect waiting in a queue for hours will be quite a bit more of a delay factor than a few minutes of buffering.