Lol I absolutely love the layout (status bar and everything.) Maybe instead of the click wheel though, just make it look like the standard iOS music player, just add the pause, volume, etc. just under the cover art.
So many actions to change volume. Shuffle and repeat buttons not suitable. Hard to understand where is song playing with round rewinder. Display is square and that is a reason why big round elements is waste of space (I don't mean cases when they have special features, i. e. controller in game).