DeaDBeef has support for title formatting scripting, like foobar2000, which allows you to customize group patterns, the converter output, the window titles, etc. to your needs. DeaDBeeF also has a Design Mode, which allows you to add new widgets to the interface and move/delete existing ones.

It's plugin based and there are many plugins available like lyrics, artist informations, visualization.

DeadBeef uses few system resources, making it great for low end systems and for those requiring a media player that uses as few resources as possible.

It does't depend on any frameworks like phonon or gstreamer, you could for example run it with mp3 or flac support