Personally i wouldn't do it. The Macbooks doesn't seem to be using the Speedstepping properly or something, because it gets extremely hot, even when idle. Obviously closing it so you can move from your kitchen to your bedroom is not a problem, but if you're going to spend hrs listening to music, i would certainly be worry about the heat damage (and certainly do not use it closed in a bag).
I returned my Macbook (at a loss) because of the heat. Unreal that a 13" laptop with onboard GPU can produce that much, even just idling. Maybe once i have some kids, then i'll be brave enough for the Macbook.