For myself I like to listen to music when I write, especially to block out noise. In On Writing, Stephen King has this to say:
"I work to loud music--hard-rock stuff like AC/DC. Guns 'n Roses, and Metallica have always been particular favorites--but for me the music is just another way of shutting the door. It surrounds me, keeps the mundane world out. When you write, you want to get rid of the world, do you not? Of course you do. When you're writing, you're creating your own worlds."
Sometimes I just need it quiet so I turn everything off with the shades drawn and the lights out. Or I head to my Other Office (see pics below). Other times I have a couple writing playlists on Itunes, usually set to random. Lots of Johnny Cash, Bob Dylan, classical, guitar. Sometimes I need just instrumental stuff, other times my writing mood gets a boost from a soundtrack. How about you?