You have many choices. Go to any New Age section of a large music store and test the choices available. The music you choose should be wordless. You don t want to add thoughts to your meditation through the lyrics of a song. You can use a wide variety of music.
Electronic music has a particularly good vibration for meditation.
I recommend music by Zazen, or Tangerine Dream. The music of Zazen was written to help you with your meditation practice. Music helps you to shut out the noise and distractions of the outside world. Be careful now, don t get so into the music that you forget the purpose of sitting. Your intent is to quiet your mind.