Like all programmes, films, etc., music has a large part of making the overall experience.
Music can sometimes make films/programmes just that little bit better sometimes.
For instance, as someone pointed out, the 'Badger Girl' music.
While I admit that 'Badger Girl' holds many nostalgic memories for me, it is admittedly a little on the bland side as a play, but the score for it creates such a beautiful, nostalgic and relaxed atmosphere that it makes it all that more interesting - it makes the play seem like one of your memories.
In my opinion, audio and visual help each other pricelessly, and cannot exist without the other (can you imagine Hitchcock's 'Psycho' without Hermman's screeching shower murder score?).