|The "SiK" interface :P...|
ZiK is a audio player (front-end actually) that uses the Gstreamer multimedia framework. So any audio file that Gstreamer plays (oh, it plays a lot... a lot) ZiK WILL play 'em too. But as mentioned before, it lacks some of the features that are becoming a standard part of a music player nowadays.
For instance, it uses the real path of your audio file rather than categorizing them as with an album. But it do support playlists, web-based radio channels, audio CDs, edit file tags and playlist editing are few of its main features. It's written in GTK+ and can even change the "skin" as well.
If you use Ubuntu 11.04 or any recent version then you can install ZiK player using the below command in your Terminal.
sudo add-apt-repository ppa:vinc-mai/zik/ubuntu
sudo apt-get update
sudo apt-get install zik