Audacious is a free, lightweight audio player based on GTK2, which is focused on audio quality and supporting a wide range of audio code. Audacious has full support for Winamp 2 skins, and as of version 1.2, some free-form skinning is possible. Winamp .wsz skin files, a type of Zip archive, can be used directly, or can be unarchived to individual directories.
Install Audacious in Ubuntu
Audacious audio player is available by default in Ubuntu repositories.
sudo apt-get install audacious
Good plugin support. List of available plugins here.