Country music is supposed to stand for something, even if no one can decide exactly what that something is; you're supposed to be proud to be country. The music has a historical and mythical connection to rural Southern white culture, even though today's performers and fans are often neither Southern nor rural.Musically, it's all over the map: lately I've been hearing country songs that draw influence from rap (mostly in the speed and style of the vocals; Talking Blues are usually more conversationally paced) and lots of hard rock guitar. Sometimes it just sounds like "rock with twang" but sometimes it really does draw on those mountain roots.
More than anything else, it's the range of topics which distinguishes Country from any other genre besides Folk: they sing about family, about religion, about life and death, about relationships (yeah, everyone does), about history and changing communities. I'm more likely to react to the storytelling and topics of country music than I am to respond to any other genre on the radio (except for folk, of course, but it's not on the radio much).
When NPR isn't on, and I'm in the mood for something lively, it's Country.