Based on both the Songbird Music Player's Purple Rain theme and my Equinox Leopard's Dark theme (http://gnome-look.org/content/show.php/Equinox+Leopard-Standard+and+Elementary?content=128861), I've created a theme that blends the rest of your Gnome apps to Songbird. I've been a fan of Purple Rain which I believe is a better look than the original Macish Gonzo look, and thus chose to make a theme based on it.
Be sure to extract this to your ./themes folder than add it in your Appearance Window. There is an image file also included that serves as a transparent background for your panel that you must manually add.
Icon theme used was iRaveH2O 3 Night Edition. This will also work well with both Ubuntu-Mono-Dark and Faenza-Dark icon sets too.