Voted for Classical Music.

I mostly listen to Classical music these days, because I hate almost all the contemporary music played on the radio, and I find the music played by retro radio stations boring. It seems to be designed to lull you into a stupor.
BBC Radio Three plays quite an adventurous selection of classical music, and sometimes jazz or even dub reggae. It's ironic that the radio station that plays the oldest music seems to be the most adventurous one these days.
BBC Six music plays quite adventurous contemporary music, but it's only available on digital so I can't play it in my car.