Hey,
   I'm playing tunes from Slacker, and it's not immediately clear what the music source is.  The first line is "Add to Slacker Favorites" which is a good clue, but only a couple lines further down, there are several "Rhapsody" lines.  The Slacker doesn't have any emphasis.

Perhaps a mini-icon in now playing should show the source, at least to tell the difference between local music and streaming music.
-C