Support for transcoding all supported audio formats using the Converter component (requires external commandline encoder executables for different output formats).
ReplayGain support - both playback and calculation.
Customizable keyboard shortcuts.
Open component architecture allowing third-party developers to extend functionality of the player.
Wine configuration
This is with a clean configuration directory and running in a 1024x768 virtual desktop.
$ winecfg
Once the .wine directory is built the configuration tool will start and you can set a virtul desktop in the graphics tab if you wish.