I'm running an XBox360 HD-DVD expansion drive to run my HD DVD movies. Yes, it's cheaper than the standalone units. However, the XBox360 HD-DVD drive doesn't decode DTS. This was the most complained missing feature by HD-DVD enthusiasts, hence making the standalone a better choice. Last I read somewhere, an MS employee is looking into this problem. But on the other hand, HD-DVD movies that are encoded in DTS is not common. In fact, Transformers isn't even DTS. As well as 300, Batman Begins, and Enter The Dragon.