DVDs are natively encoded as 480i, and special flags are used to tell your DVD player how to reconstruct the original progressive film frames. It's not always done properly though, and then your DVD player has to incorporate sophisticated cadence detection to perform the deinterlacing. I'd like to avoid the same mess with HD-DVD, which means 1080p native.

Again, Sony recently announced they are considering other codecs. They are no longer taking the hardline stance that MPEG2 is the only way they're going. This is an important step toward Blu-Ray winning the war, but it's still up in the air until Sony gets their act together.