21. Kate and Anna McGarrigle, 'The McGarrigle Christmas Hour'
Kate and Anna McGarrigle were a brilliant Canadian folkie duo, now more famous for Kate's children (Rufus and Martha Wainwright) than their brilliant '70s albums. On this 2005 album, they recruit their family, plus friends including Emmylou Harris and Beth Orton, to do songs that range from "O Little Town of Bethlehem" to Jackson Browne's "Rebel Jesus." It's a homespun affair, with an emphasis on celestial harmonies – and it was the last album they made before Kate died.