When coding, it is either old school electro : https://www.youtube.com/watch?v=QpDn4-Na5cohttps://www.youtube.com/watch?v=DY1s9SmrQRE (this one is not actually old, but the style).
Or classic rock like airbourne.The harder the problems gets, the harder the music needs to be :) For hard problem, I suggest http://schizoid.in/ 's psychedelic trance channel.