Often suprised by the amount of C# development happening around GStreamer. Especially suprising as the GStreamer C# bindings are still only available from the Mono CVS repository as far as I know. Anyway I was pointed to a new media player application today called the Maxima-MediaPlayer.
Also of recent interest is Sonance which is licensed under the X/MIT license and also have its development sponsored by Novell.
Been playing music using the GStreamer 0.9 version of Jamboree today. Works well, with instant song change when next is pressed. Being rather experimental it do crash on me about once per hour, but still for something which only 2-3 people have tested so far it works well and is stable. Jan have hinted about having a Rhythmbox port to 0.9 ready soon too.