Thanks to my younger son (turning 2 on Valentine's Day), I've become a huge fan of
WRFG (Radio Free Georgia) 89.3, Atlanta. They have a 4-hour blues show every weekday morning, and our boy can't get enough of it. They play an extremely wide variety, and none of the people involved are trying to "take the next step," they're just sharing their love of whatever music they're passionate about.
As a younger person, I swore by
WRAS 88.5, but not so much now. Maybe I changed, maybe they changed, maybe both of us changed, but I can't wholeheartedly recommend Album 88...