She has family cred:
Martha Wainwright (born May 8, 1976) is a Canadian-American folk-rock singer-songwriter. She is the sister of Rufus Wainwright and the daughter of Loudon Wainwright III and Kate McGarrigle.
I have to admit I never heard of her till listening to her version of one of my favorite Pink Floyd songs, See Emily Play written by Syd Barrett: quite a haunting version of it in fact.
Background: The song was reportedly about a girl named Emily, whom Barrett claimed he saw while sleeping in the woods after taking a hallucinogenic drug. Barrett later stated that the story about sleeping in the woods and seeing a girl before him was made up "...all for publicity."
According to A Saucerful of Secrets: The Pink Floyd Odyssey, by Nicholas Schaffner, Emily is the Honourable Emily Young (b. March 13, 1951), daughter of Wayland Hilton Young, 2nd Baron Kennet, and nicknamed "the psychedelic schoolgirl" at the UFO Club.
An article in Mojo magazine called "See the Real Emily" supposedly shows a picture of Barrett's Emily.
Martha doing Far Away (pretty, up close video):
And being a Wainwright, you must do a Leonard Cohen song (or two). This is
I'm your man (2005)
followed by her brother Rufus singing Hallalujah from Shrek: