Impossible question, from the perspective of this Irish American. We have such a varied musical scene and tastes that it would be based on what type of music one is talking about. Depending on the genre, Nashville, New York, Dublin, Chicago, London, Liverpool, Austin, Paris, New Orleans, San Francisco, and on and on.

I think the better question is "What city is the center of your musical world?", and I am not at all sure that could be answered.