Growing up, it was KISN on 97.1 in the mid 1980s-late 1990s, as well as its sister KKSN on 910 (later 1520, in QAM stereo even.) Until about early 2008, it was the Golden Hours RRS on OPB and the "Environmental" and "Forground Music One" satellite programmes on Muzak, although those three are not technically "radio stations" in the generally accepted sense.
As it stands right now, I can't think of one in my native corner of the Cascade Range that fits, because they are pretty much all bland, lifeless jukeboxes now.
But, considering the way the weather in northeastern Oregon been as of late, my Best Radio Station Ever would have to be the simulcast of NOAA's WNG708 on 1610!