I think you would be happy with the hE500's for your music genres. They sound great with electronic music. I personally wouldn't want any more bass or top end for dubstep etc. They've got just the right balance for me. Also I'm sure you'll appreciate the great mids with rock music too, guitar sounds very good. But as has been said, you may very well appreciate a more fun type phone such as the HE400's. (haven't heard) I find the HE500's to be the more "fun" hp compared to my LCD2's as they are more dynamic and have such an addictive treble. It's smooth and none fatiguing yet sharp and fast... Well done Mr Fang!
Excellent, great feedback! I guess I'll have to decide if it's going to be the HE500 or HE400 for me then :)