It really depends. When I'm training for Kumite, I listen to alot of Metallica, Slipknot, Static - X, Alice in Chains, Shihad (New Zealand Band), Slayer, Rob Zombie, Disturbed stuff with alot of aggression Kata, I either have nothing on, or Linkin Park, Incubus, Urban Techno just stuff that carries alot of emotion. (One of my favourites is Linkin Park - Points of Authority, great for a long Kata)