I keep hearing advertisements for HD radio. The car stereo I replaced my stock one with happens to have HD. In Minneapolis there are about 4 more radio stations, in Madison, WI there are about 2 more radio stations, and in Milwaukee there are 2 or 3 more radio stations available. And of those new stations about half seem to be alternate NPR stations.
So, I recommend ignoring HD stereos, unless you live in Chicago or NYC, which may have more than a few more NPR stations.