The xylophone. A somewhat unloved, or at least relatively ignored, instrument in terms of soloing / providing a blazing riff. Below is a current favourite song containing a xylophone solo which completely slays.
Roy Ayers - Coffy Is The Color http://www.youtube.com/watch?v=l9X1Jkv48po
I'd like to hear a few more good ones. What've you got for me?