HD-DVD is dead - but they did one thing really well: they released titles with HD-DVD on one side, and normal DVD format on the other side. This was great because with one purchase, you could play the disc wherever you may roam.
Blue-Ray hasn't taken this approach. You buy a Blue-Ray disc that only plays in Blue-Ray players. I hope this has something to do with double sidedness and not marketing. They are packaging an iTunes version with some releases and this is great, but it leaves me out in the cold in a few particular situations.
The biggest one is the car. People don't buy cars every year. And as more and more family trucksters have DVD players in them, they are only putting in normal old DVD players. This means none of your Blue-Ray discs will play in your car.