This may not be to some people's taste, both the music and the video direction is a little odd. But I find the little boy dancers absolutely enchanting, and there's something very rich in Fiona's voice.
This is the song Paper Bag, and the music video was directed by Paul Thomas Anderson, who recently got acclaim for directing the Oscar-winning movie There Will Be Blood. At the time of this music video, they were dating.
Perhaps this explains the video's slightly strange, but still pleasant, take on the song.