Rhythmbox 3.0 made it out this week for the GNOME 3.9.91 Beta and with the 3.0 release its plug-ins now use Python 3 rather than Python 2. Additionally, there's a new task progress bar, support for composer tags, restyling to icons and other user-interface elements, better introspection of everything, playlist settings in a XML file, and various other fixes. There's also a long list of bug-fixes.
If you use Rhythmbox as your GTK+ music player, Rhythmbox 3.0 looks like it's worth checking out. More details can be found on the Rhythmbox mailing list.