You know, Toshiba won’t exactly be helping Blu-Ray adoption anytime soon by dumping a raft of players on the market that, in addition to playing HD DVDs, are extremely good upscaling DVD players in their own right, including being the only dedicated players I’ve seen that handle pillarboxing of 4:3 DVD content over HDMI correctly. At sane viewing distances, I suspect most non-videophiles couldn’t tell the difference between an upscaled DVD and high-def anyway—Jennifer Morrison doesn’t look any different in HD and upscaled DVD that I can tell.
That said, I can’t figure out why you’d even spend $50 at this point on an XBox HD DVD add-on, since it doesn’t upscale DVDs any better than the built-in DVD player on the box.