Alison Krauss

These are Krauss's deeper roots, and here with the famed Cox family, she outdoes herself. There's a hint of Dolly Parton in her vibrato and regionalisms, but overall Krauss is incomparable. She fills roles large and small, from belting out folk songs to singing backup vocals. But the magic is in her sweet soprano whispers; add a twang and a hymn, and it's heaven.