FMQB reports that Best Buy will start selling HD Radio receivers at all 832 stores nationwide. They're also "increasing emphasis on HD Radio in its weekly newspaper ad circulars and in stores."
If Radio Shack's selling of the Boston Acoustics Receptor HD & Accurian HD table radio was the first big step in HD Radio adoption amongst listeners, then this is definitely the next big step. Despite a lot of questionable customer service practices by Best Buy, they are certainly one of the premier electronics retailers. We have a bunch of 'em here in Boston.
Now I just hope that Best Buy actually educates their salespeople to know what HD Radio is. Historically they have not been good about this...often I have gone into Best Buy and asked if/when they'll start carrying "HD Radio" and they'll take me to their Sirius Satellite Radio display. sigh
Still, I'd say that we're rapidly approaching the second big wave of adopters. We've already had the hard-core early adopters who were actively seeking HD Radio receivers through any outlet they could. Now we've got the more moderate early adopters who want HD Radio and have options at common retailers to get them (Radio Shack, Walmart, Best Buy). Probably within another two to three years we'll see HD Radio receivers start becoming "commonplace" enough that the next wave of adopters will hit: the everyday users with disposable income.
This does have significant impact on broadcasters transmitting HD Radio as well...no longer can they assume that there's no (or few) listeners so they can "get away" with poor engineering, operations, or dead air while they figure out what to do with HD Radio. School's almost out, kids! :-)