I figure this...I don't have a 1080p display. I want future-proof 1080p products as much as the next guy, but, as I thought about it and my situation (I own a lowly circa-2004 720p Sony RPTV...boo hoo. I'm holding out a couple of years for a next gen SED full 1080p set w/ contrast ratio beyond belief), I realized that 1080i will do just fine.
I figure, in 2 years, we'll see if an upgrade of my console is warranted. Hell, there may be an entirely new Xbox system on the horizon by then. Would love HDMI--I'd hope they'd provide a peripheral path for original 360s for that, though. We'll see.
If they want to release expanded content games using HD-DVD...I say bring it on. They should be able to do that utilizing the add-on for legacy console owners no problem.
Why would anyone NOT want that option?