These days, developing is usually best with chip tunes, lord knows how many hours I've spent developing / planning with the Game Music Bundle soundtracks (Disasterpeace, Armcannon, etc.) in the background.

Or anything that's really musically technically demanding, with minimal (or at least ignorable) lyrics in the background (A Wilhelm Scream, Minus the Bear, etc.)

Thank God for RDio, it's pretty dependable for pulling that stuff out of thin air when necessary..