The song you just cant stop playing???

Loreena McKennitt: 'The Visit' - Bonny Portmore.
Eva Cassidy: 'Songbird' - Fields of Gold.
Chris Botti: 'Thousand Kisses Deep' - My Funny Valentine.

I think what I find so appealing about these cuts is that they are down-tempo, laid-back and sparsely arranged. Very intimate and lots of ambiance.