One of the greatest radio stations in Philadelphia history, WDRE 103.9 was a fairly underground station, playing punk rock and alternative music, from 1992-1997, when it was bought and made into a hip hop station. It was the only commercial station in the area where you would hear Husker Du, The Velvet Underground, early Replacements, and the Sex Pistols.
One of the cool things about 'DRE was the Sonic Session, wherein bands would do small sets for about 30-40 people, and then the show would be broadcasted on the air about a week later. Y-100 currently does this, but the quality of artists just isn't there--Three Doors Down? This is alternative?
Nothing has really taken its place, though WPRB 103.3, the Princeton University station, can be quite good, playing even more underground musicians like The Mountain Goats and Nomeansno.
When WDRE was killed off, Y-100 "tried" to pick up the slack, but they're only poseurs, considering Pearl Jam and Alanis Morissette "underground." It makes me wanna vomit.
UPDATE:
In the years since, Y100 has been turned into an R&B station, WDRE became a gospel station, and the only commercial station playing alternative is 104.5, owned by Clear Channel, so you can imagine how thrilled I am.
Well, there's always PRB...