I own about 5k cds and by far, I listen to my Eva Cassidy collection the most frequently. I find not only her voice but also her songs to be very entertaining and enjoyable. My favorite Eva cd is probably Imagine followed closely by American Tune.
Spencer, good call on Tracy Thorn. I have not liked EBTG since Amplified Heart after they got all techno. I had the pleasure of seeing EBTG at the Coach House where I was literally 5 ft away from Tracy and Ben. It was a great, intimate show. I have all their albums including Tracy's solo project (A Distant Shore) and it is really cool to hear the maturation of her voice from a very monotone presentation to one that evokes emotion.