You may run into a problem if a track has more than one artist.

You'd have to enter the track for each artist again, or you'd have to only use the first artist, or you'd have to create a new "combined" artist.

Why not omit the artist→track hierarchy?

<collection>
  <track>
    <title>Thriller</title>
    <artist>Michael Jackson</artist>
  </track>
  <track>
    <title>Hey Jude</title>
    <artist>The Beatles</artist>
  </track>
</collection> 

Benefits:

• You can add more metadata for tracks (composer, album, etc.)
• You can add tracks without title and/or artist
• If different artists may the same name, you could id'fy the artist elements

You may run into a problem if a track has more than one artist.

You'd have to enter the track for each artist again, or you'd have to only use the first artist, or you'd have to create a new "combined" artist.

Why not omit the artist→track hierarchy?

<collection>
  <track>
    <title>Thriller</title>
    <artist>Michael Jackson</artist>
  </track>
  <track>
    <title>Hey Jude</title>
    <artist>The Beatles</artist>
  </track>
</collection> 

Benefits:

• You can add more metadata for tracks (composer, album, etc.)
• You can add tracks without title and/or artist

If different artists may have the same name, you'd need a way to differentiate the artist elements; e.g. by using id with an ID of an artist database.