I dont understand why the future lays in a large disc. At the end of the day why dont they move to a model whereby you have abox that does the digital wizardry from a stream of data (ie the sound and video processing, PVR functions, etc). And a standard interface that can accept a stream of data from any media.
Then all you would add would be a drive. That drive could be the choice of the individual, wether it be HD, DVD or Blue laser. So for example if IBM managed to make 50Gb microdrives, instead of a bulky DVD player you would just need a compact flash reader to plug into your AV kit. Formats would be up to the individual and the AV bit would be format independent, the only thin to decide would be the interface and that could simply be an extension to ide, scsi, firewaire or USB so its not reinventing the wheel
I know Im talking HTPC here, but not many people want a monolithic white box with a keyboard in their living room.
A nice Hifi sized box that has all the video functions and the media its using as a seperate box.