Ann Oliveri now has posted twice about creating a distinctive soundtrack for your meeting as a way to engage people in a multisensory way. I like the idea of creating your own song and using it as people filter into general sessions, etc., rather than a playlist of popular songs (that you'd have to pay royalties on, as one Acronym commenter noted). Something distinctive that would brand your conference as much as the logo, maybe.
Then again, conferences often are kind of aural overload already, at least for me. Between the background noise of hundreds or thousands of people chatting, to (usually way too loud) musical acts and keynote speakers, to the general city noise--hey, I'm a country girl and all those sirens and horns beeping make me edgy--I don't know if adding more tunes would give me a positive vibe or not.
Then again (again), I loved the musical spoofs ASAE did last year, and Jason Alexander's opening number at PCMA could become an anthem for meeting planners everywhere. So, I guess mark me down as ambivalent. I know the one time I brought in tunes to set the mood for our regular editorial meeting, it went over like a lead balloon, but maybe they just didn't groove to Krosfyah the way I do.