Seattle's C89, even though a public radio station that is ran out of a High School, has the best variety of dance on US radio in my opinion. First of all, C89 is partly responsible for bringing such acts as Lady Gaga to the mainstream. C89, which different from other dance stations like SF's Energy, brings more European acts to their playlist, such as Calvin Harris, La Roux, Royksopp, etc. Also, C89 always seems to get to a new dance track before any other station in the country, which I find very sad that a public radio station from a High School in Seattle can see the trends before all these major market dance leaning stations. And being a public radio station, having no commercials sets C89 even further up from the rest! I'm sure most of you have, but have a listen sometime and compare to others in the US, and you'll more than likely agree:
http://c895worldwide.com/web/default.asp?page=music
http://c895worldwide.com/web/default.asp?page=music