I have different levels.
If I'm just doing admin style work I can have any music playing and even sing along to some stuff.
If I'm doing some basic programming/data work I'll have instrumental music on. Usually film scores by the likes of Clint Mansell, Mark Korven, Ben Frost.
If I'm deep in debugging/complex programs/methodological work I'll listen to a lot of Merzbow (Japanese noise. No melody, rhythm, lyrics etc. Just noise to obliterate external distractions)