A few years back my youngest sister gave me a Loreena McKennitt Christmas EP, and I fell in love with her voice. While not my normal fare for everyday listening, it certainly is nice for certain occasions. While not all my selections are Christmas songs, this first is called "A Midwinter Night's Dream"
This is a musical setting of the Yeats' poem "The Two Trees"
Finally, this is "The Mystic's Dream" recorded live at the Alhambra in Spain.