I partly agree with the two distinguished British gentlemen. DVD is good enough - as long as you are not using anything larger than a 32 inch HDMI LCD. With larger plasmas and better than average projectors/screens there is clearly a need for more resolution.
But look at the hi-rez sound situation. Total confusion. No less than 8 (eight!) formats to be found in the better than/different to CD-section in the shops: SACD, DVD-Audio, LPCM 24/96 and 48/96 (sometimes called "enhanced audio resolution), DTS 2 ch 24/96. Not speaking of compressed DD and DTS multichannel - AND uncopressed MLP multichannel! (Did I forget something?)
You never know which player that supports what, which makes it highly risky to buy into the high end side of the hi-rez market. People who like to try some of the formats out is likely to end up with inferior multiplayers that do neither of the new formats any justice. In some cases, the sound is worse than standard CD.
A similar situation could emerge with hi-rez video. With possibly the same result: People stick to DVD, as they still buy CD. And of course they download their music from the internet, legally or illegally. With consistantly worse sound than CD. Did anybody mention the word progression?