This might only work under OS 5.0 but anyhow... if you put the music player on your convenience key (right or left), click it once, launches it... click it again launches Now Playing. Very handy. Discovered by accident.
If you use your Tour for music this is a great find (not just because I'm in love with my own ideas). There's no way to put Now Playing on a convenience key... this hidden feature is probably the reason why.