The Pogues - "Fairytale of New York" (2nd demo) Recorded in 1986, and issued on the recent box set, Just Look Them Straight In the Eye and Say. . . Pogue Mahone!! (buy) (Highly Highly recommended). The woman's vocals which would later be recorded by Kirsty MacColl for the classic version are performed here by Cait O'Riordan, prior to her departure from the band.
The box set includes three different demos of the song, with lyrics and music changing as the writing progresses. If you're a Pogue fan, and you don't yet own this box, it should be at the top of your Christmas list.