Romantic Music

If you've ever watched the World Poker Tour, you've seen the Michelob Amber Bock commercials, first showing someone who's "rich, but not smooth," then someone who's "smooth, but not rich." In one of the ads, the "rich, but not smooth" guy, in the middle of a romantic encounter, says, "How about a little music?" It seems to be a good idea, until he starts playing some over-the-top hip-hop tune and dancing around like a maniac.

Okay - we've established that you don't want to be like that guy. So what music do you play to set a romantic mood?

Some general rules are in order:

Instrumental music is better than music with vocals. I know, there are a lot of great love songs out there with words that get to you; but love songs are love songs, not mood music. You don't want to be sitting on a couch whispering sweet nothings in someone's ear only to find out that she's been listening to the words of the song, and didn't pay one bit of attention to what you said. Oddly enough, this problem disappears if the words are in a language neither of you understand, like Enya singing in Irish or (assuming you don't know the language) just about anyone singing in French.
Soft is better than loud. No explanation necessary.
Melodic is better than rhythmic. One wants swooning, not toe-tapping.
Classical music is not mood music, with the possible exception of classical guitar music.
Old songs are better than new songs. Why? Old songs are familiar, so you don't have to work as hard to listen to them. Old standards are safer than new songs, and safety is a good thing.
Mellow instruments are better. Some instruments lend themselves to mellowness, like muted trumpets. Some instruments can do a lot of things well, like the piano, so mellow piano tunes are great. Some instruments - bagpipes, fifes, and cymbals come to mind - just can't be mellow.