Everyone knows how big a difference music can make. The right song can make a movie scene unforgettable, or turn a commercial about two dudes driving around in a car into a classic. Here's my favorite new example of how radically music can alter the tone and meaning of picture (a tad long, but makes the point):
Traditionally, the music is the responsibility of the copywriter (though I've worked with many art directors and producers with encyclopedic music knowledge, which is awesome). But it's one of those things that you don't learn about in ad school.
What I'd recommend to any aspiring copywriter (and art director, for that matter), is that if you're not into music, get into it. Force yourself to listen to types of music you wouldn't normally listen to. Expand your musical world. There are tons of great resources out there to help you do this. Read Pitchfork. Listen to the podcast of Sound Opinions. Listen to Pandora. Or check out one of my favorite Internet communities, the International Mixtape Project.
The point is that, as Greg pointed out in an earlier post, you need to be able to communicate with your vendors. This includes musicians. Having a decent working knowledge of music types and being able to speak the language makes the process a lot easier. You don't need to know the difference between an 8- and 12-bar blues, but be able to give direction to a musician in a general sense. Like whether you want Johann Sebastian Bach or just Sebastian Bach.
Those of you who are into music, where do you find new stuff?