Here is an interesting read about how the audio in HD TV is not keeping up with the video.  People are buying 1080p TV sets.  The networks are paying more attention to the quality of their video, but they are not yet doing much with the audio.  Many movies recording in 5.1 are broadcast in 2 channels. 

The article posits that this will change in 2009 when everything goes digital.  I'm not sure I agree.  Most everything is practically digital today.  There are people watching SD with rabbit ears, but they're in the minority.  Most people get their TV via cable or satellite.  Even so, there's still a whole lot of SD content out there.  Will turning off the analog broadcast airwaves make the need for that SD content over cable go away?  Probably not.

This article also highlights the tension between audio engineers and those holding the purse strings.  How much do people actually care about better quality audio?  The failure of SACD and DVD-Audio along with the heavy adoption of MP3 even in its overcompressed form would seem to indicate not nearly as much as we audio types would hope.

http://production.broadcastnewsroom.com/articles/viewarticle.jsp?id=329804