I think using a standard toolbar is a great idea.
The standard toolbar is great for customization.
I for one would certainly get rid of the Search Box if I could. (not to mention add a Stop button XD )
Some feedback:
-IMO, a Volume knob is neat as an imitation of a real life counterpart, but in terms of usability, it's one of the worse choices for an app control. Making your hand go left/right or up/down in a precise manner is relatively easy; making it go clockwise/counterclockwise in a precise manner... not so much.
Personally, I think a good ole' Volume slider would be best.
-I also hope the seeker bar will look more like the current one.
-Otherwise, looks great. ('cept for the placeholder icons, of course ;p ) This looks promising.