Over 3,000 songs and no "MTV2" music on your laptop? fair play - thats quite an impressive feat....
You just said that people will want to hear different songs by different artists - so maybe you should consider putting at least a few "MTV2" songs on your laptop - I know its not at all your thing, but when I was at the dog and muff there were a fair few people there who were into that kind of thing......
As for metal though - I request a bit of In Flames, Soilwork, Nine Inch Nails, Tool, At the Gates and Soulfly - couldn't find many songs by each of those artists when I was playing about with your laptop last time