XMMS2
I'm a XMMS2 developer. In the beginning, I used to hack it every now and then because of Euphoria development, but nowadays I'm mostly working on XMMS2 instead of Euphoria.
Subsystems/plugins I maintain are the Ruby bindings for libxmmsclient, the replay gain, wave and diskwrite plugins and also the ALSA plugin (together with Daniel Svensson). I do work on anything that needs fixing though :)
I also wrote an AudioScrobbler client for XMMS2, find it over there.