Almost always silence. Sometimes if I'm having a bad mood of some kind, I'll put on something that's soothing or uplifting for me, basically just any of my favo

Almost always silence. Sometimes if I'm having a bad mood of some kind, I'll put on something that's soothing or uplifting for me, basically just any of my favorite music that isn't too sentimental or lyrically interesting... but mostly, I find it easiest to concentrate in silence. (This makes it annoying to work in environments where the only way to not overhear conversations is to put on music in headphones...)