It depends what mood i'm in, for example - when i'm working out i listen to heavy death metal (i listen to Dethklok, great heavy metal band)
when i'm feeling random i listen to short tunes such as the sandwich song (can be found here- <a class="postlink" href="http://www.youtube.com/watch?v=wUDqQSwdBjM">http://www.youtube.com/watch?v=wUDqQSwdBjM</a> )
when i feel like i need to punch something i listen to epic/classical music