Every time I attend a local scbwi meeting, I want to ask the other illustrators what they listen to as they work, or who their illustration heroes are. I love comparing notes on things like that. I think it gives you a fun glimpse into who that person is. Alas, there never seems to be time because I find myself equally anxious to see what everyone's been working on. Also, I'm an introvert, and its much easier to talk to the person next to me (or not talk at all) than attempt to open up a group discussion.
The truth is, 90% of the time, I work in glorious silence. My home is deliciously quiet for 7 short hours a day. In the half-hour countdown before my children burst through the door, I find myself bracing for the jarring, happy chaos. So I tend to relish the lack of audible stimuli when it is within my control. Every now and then, though, I like music. (I loved it from elementary school through college. What happened?) Most recently, I worked for hours one day listening to decades-worth of Billy Joel. I loved his music as a kid, but the weight of his lyrics and the diversity of his style were totally lost on me then. This was like listening to most of it for the first time or with brand new ears. But I digress...
Otherwise Adele is my default but other guilty pleasures include Weezer, Fall-Out Boy, The Beatles, Crosby Stills and Nash, Broadway soundtracks, MoTab, and (whether I'm in the mood for it or not) my children's selection of Parry Gripp songs or their favorite popstar flavor of the week. (Not an exhaustive list, but you get the idea).
What do you listen to when no one else is around?