As a recovering headbanger, I listen to http://www.totalrock.com some. They are located in London, and crank out some good heavy metal. Since it's real late at night there when I normally listen, I get to hear some of the wackier djs. The take requests by email, and play them often.

My fave though is the Dividing Line.  http://www.thedvidingline.com  The first show I started listening to was Gruno's (he shows up pimping his show from time to time on this board) but now I listen to several of them. The djs are strictly hobbyists that each has a weekly show, and they play almost anything one requests. They just upgraded their server, so the audio streams nicely. With the exception of Gruno's show, the station is primarily "prog", so you have to tolerate crap like Genesis, Peter Gabriel, and Yes - but along the way can hear some new and rare stuff that is pretty good.

I would like to find a station that plays more of the singer songwriter type stuff. There are a lot of artists that people mention on this board that I would like to hear..