I am on a lifelong mission to annoy Victoria Weaver by saying:
MAHLER!!!!
But if I’m to be completely honest, it’s Bach.
Mahler, because of the cathartic emotional extremes, the amazing orchestrations, the largescale forms, the cogent narratives.
Bach above Mahler, because of the sublime joining of intellect and passion, and (I hate to admit) because it can communicate to you even if you aren’t paying rapt attention (which is why I default to it at work).