"CD-quality sound" and "no more interference" claims won't get people buying HD Radios. HD Radio will only work for stations who have a reason to need the multi-cast capability and interference-free signal. for most stations it's a waste.
I think the only station having any success with HD is WRTI. finally you can listen to their classical music in the car without losing half the music to poor signal/noise performance and other interference. and with their HD2 they're finally providing their audience 24 hours of classical and 24 hours of classic jazz. I'm told that their while their HD2 is all automated/satellite programming, they get a ton of phone calls from people when there's a major problem (as happened labor day evening when the automation crapped out and left the satellite jazz service on all night instead of switching to classical. apparently, murphy works holidays.).
I do like WYSP's HD2 simulcast of KYW. where I live in south jersey, KYW's AM signal is not very good. in the car it's almost abysmal. and although KYW-AM is itself HD, it's not reliable enough because, again, the signal isn't good. but 'YSP's HD2 is pretty solid so I can listen in the car again.
that being said, I agree with sam that there really isn't much of a future for HD. not from any of the other secondary programming choices I've seen. the only thing that will drive HD to any point of real success is different, unique, entertaining, engaging programming. but by then we'll have ubiquitous wi-fi (92?) or wi-max internet access and the jig will be up. give the BBC's Radio 2 a listen (
www.bbc.co.uk/radio2) especially weeknights between 7pm and 6am ET. it's the UK's number 1 radio station. it'll sound strange to the ears and sensibilities of American broadcasters, but THAT'S the kind of unique programming we need. nobody's got the balls to try that here I'll bet...