+1 on the sennheiser hd-25 II's.
They're pretty much the industry standard for DJ's all over the world for their excellent isolation, full frequency spectrum (super and powerful deep sub bass and nice treble) and the fact that the cable only connects to one side = no twisting cables. They can play very, very loud. The sound quality is very detailed and sharp.
They're quite big, but they're partly foldable.