Noise
I have an Xbox 360 and a HDTV, but I'd never buy this. As mentioned before, it looks like HD-DVD might well lose the war, but the main point for me is the noise that the Xbox 360 makes. I won't use the 360 as it stands as a DVD player because it is too noisy during the quiet bits, and apparently running HD-DVD movies means it is running at almost full processing, which means even more cooling noise.