Here's an interesting one. Reportedly, the copy of 300
that comes bundled alongside the Bourne Identity in any of Toshiba's third-generation HD DVD players completely omits the DVD side found on the traditional
combo disc. Granted, the content on the HD DVD side remains exactly the same, but since the vanilla DVD held exclusive audio commentary, it seems that this particular disc adds "its own exclusive picture-in-picture video commentary" to compensate.