Pokertracker/pokerace hud means I dont have to pay as much attention as I would if I wasnt using such tools. I have a TV card in my PC and watch TV whilst playing poker, and I'm doing ok. I watch who bets first and how much, but the more brain-intensive memory parts of how a player is playing are handled by the software.

Even people like Daniel Negreanu will sit there in a tournament with headphones on.

Playing poker requires a certain mind-state. If you find that listening to music helps you achieve this, nobody else has the right to come and tell you to do differently. Do what works for _YOU_.