So far, I've got apprx. 4,000 folders worth of songs. Altogether, I've got about 105-110 gigs of music on my external. I'm a trance/dance/techno addict so name anything and I'll probably have it.
That, and almost every other recent song thinkable. I like a nice mix of music...rap, hip hop, trance, pop, dance, classical, rock, etc.