Currently visitors have the option of turning the music ON at my site. The default loaded is off. That way a potential client surfing at work isn't going to get "busted" because of the music. But if they want to listen they may.
If your visitor has the environment to comfortably listen to the music, and the music is to their taste, then it can really add to the presentation.
OTOH if your visitor is at work and gets hit with the same song that was playing on the car radio when their high-school boyfriend broke up with her then you've just lost a customer.
On balance it's not worth the risk to just hit them with it .. if you provide a button for them to turn the music on after the site loads that's the best of both worlds.
On a personal level I absolutely abhor any websites with music. So much so that when people post websites to review on these forums if I open them and there is music I just shut it.
However, I think for wedding websites it's a different kind of game. I think music is acceptable as long as you can turn it off. As to what is good and bad, that is another story entirely but I'd say, 50/50 most of the music I hear on wedding sites is absolutely terrible, or pretty decent.
I really, REALLY hate it when I see a photographer's website rip-off copyrighted music like Enya or whatever just so they can have something nice for their guests to look at. I know they didn't pay for the rights for that.