I would say it mostly depends on the type of atmosphere you're trying to provide at this party... Obviously for a dance party the songs are going to have to be upbeat and have some rhythm. If your trying to go to with hip-hop there is a great free radio station that plays some of the best rap to dance to I've ever heard. www.thugzone.com
Now if your trying to get a dance party without all the hip hop that some people refuse to like no matter how good it is, I would try artists like Prefuse 73, The Crystal Method ( IN CONCERT TONIGHT AT LIMELIGHT), Bonobo, Tiesto, and even some trippy Infected Mushroom.