I don't think that any of this answers the poster's question.
As far as the benefits of 1080p are concerned. Somewhere I read a post by someone who already owns a "mainstream" HDTV. He walked into a big box store, and was drawn to the picture on a demo set across the store. It was showing a different move that all the other sets. Upon inquiring as to what he was looking at, was told that this was a BlueRay video (on a BlueRay DVD) connected on a 1080p set. According to the poster, everything else looked absolutely inferior (I think he used a different expression....)
I'm not sure about BlueRay vs HD DVD, but a the rate technology is moving, I would expect not just HDTV, but 1080p broadcasts, software AND hardware to be the norm by 2008. I expect that once people see what's possible, the will demand it, and competition in the market place will follow, including price drops to civilian levels. That is, unless government intervenes on the side of the nay-sayers and whiners.
As far as as the changeover is concerned, according to the FCC website, there will be conversion boxes available (possibly for free if you get your progamming via antenna.)