One time an escort had mellow electronic music in the background and all of a sudden Nine Inch Nails started to play. Neither of us wanted to stop what we were doing, so it continued playing until our date was over. It wasn't intentional - iTunes screwed up somehow. Have to say, it was a very fun and romantic session.
That said, my preference usually turns to the "chill" station on iTunes, electronic riffs on Gershwin and Cole Porter (I highly recommend those compilations BTW), or the "Afterdark" series of electronic/lounge music.