I have these headphones... sony mdr-ex71
I really like them, really good sound reproduction, accurate bass but not so much that you that you can't hear anything else and gives you fatugue and also great isolation when on the underground trains.
However, they are quite hard to get set in your ear properly so I use the standard ipod headphones on my pc when I just want to quickly listen to something, but use the sonys for longer listening or when travelling to school.