A member of the Xbox 360 HD-DVD team confirmed for me today that the Xbox 360 HD-DVD drive will in fact be recognized by Windows Vista, but it will NOT ship with decoder software. I'm assuming that Intervideo will have a version of WinDVD sometime in the future that supports HD-DVD. Personally, I think the drive should come with the required software to dual-use enable the device (adding value to a non-trivial purchase), but I'm not a PM at Microsoft.