When I'm not listening to music, nearly all the time I'm imagining it anyway. It's always going in the background. Right now, it's a few seconds from the opening and closing themes from Inuyasha: The Final Act. Usually it's video game or anime music — "Big Shot," "Empty Town," "Spear of Justice," "Snowdin Town," "A Cruel Angel's Thesis," "Shizuka," "My Favourite Customer," "She is Watching Us," "End Times," and so on. For a while it was Aviators, then Infected Mushroom, then Boards of Canada, then Monomer.
When I let go of that, the world feels silent by comparison. The quiet feels enormous.