I am a web developer. Going on 12 years in the industry. So from a professional level I can say that music on a website is really taboo. The exceptions to the rule would be sites that promote music, like a bands website, and if the music is part of a short video that runs. So if you are using a website to stir up business in any form I highly suggest staying away from it. If its just for personal reasons then go for it. I personally keep my volume turned off, and turn it on only when I choose to hear something.