Let the hive mind of Engadget get that for you.
"I am looking for a device that will stream sound from one source to several recipients. For example, I want to stream sound from my TV or stereo to my phone or MP3 player that has radio and Bluetooth capabilities. I have looked into radio transmitters and they seem like a decent choice, but I can't find one that uses external power (USB or from the plug) and I would want one with a transmit range of around 50 meters. Thanks!"
Not to mention that it'll upscale regular DVDs as well. That was my one concern about the HD-DVD addon, but I wonder if the upscaling of regular DVDs is more of the fall software update via Xbox live than the HD-DVD addon. It might be a requirment to have the HD-DVD addon to get the DVD upscaling, I guess only time will tell but either way I sure am glad that it has it.