While this might be the case with the PS3, people appear to be using the Xbox 360 to watch movies. According to CNET, Microsoft has sold 150,000 Xbox 360 HD DVD drives in the US alone.
http://crave.cnet.co.uk/dvdpvr/0,390307 ... 205,00.htm
There were also some surprising stats given. Microsoft was reluctant to tell us how many HD DVD drives for the Xbox 360 it has sold worldwide, but it did tell us that in the US it has shifted 155,000 of them. This is apparently the biggest-selling accessory Microsoft has ever sold for the 360.
So yes, there are 50,000 more drives out there than stand alone players. Maybe the HD DVD Promotions Group should start including these numbers in their stats?