Depends on the project I guess and what it is I am hoping to accomplish. In general, just having any music somewhere going on helps me focus. I remember reading this article that talked about classical music helping you learn and retain information, but the down side being that the associative quality of the music is such that people would require it to be being played during a a time when they needed to recall the information. Such as during an exam. Never had an issue though. I just always keep all the music playing every moment I can. Just makes life better.