Forum:Zer0's Theme Song?

Zer0 is one of the most interesting characters storyline wise in Borderlands 2. He speaks only in Haikus, he appears heartless in every sense of the word except when money is invovled, and not even Angel can figure out who or even WHAT Zer0 is. With that knowledge and your personal knowledge of Zer0's exploits, what songs might Zer0 be listening to under that helmet OR what might his theme song be?