17. KT Tunstall
"Black Horse And The Cherry Tree" (2006, Number 20) and "Suddenly I See" (2006, Number 21)
This Scottish strummer's first single had a runaway-train feel thanks to its chugging beat and an ample supply of "woo-hoo"s – it was inspired by "old blues, Nashville psycho hillbillies and hazy memories," the singer said. But it didn't capture the ears of American audiences until American Idol runner-up Katharine McPhee performed it on the show in 2006. The optimism-drenched followup "Suddenly I See" had a triumphantly cresting chorus and inspiration from Patti Smith; Tunstall claimed in an interview that the boisterous nature that could make it seem tailor-made for inclusion in a chick flick was completely accidental. On her 2013 album Invisible Empire/Crescent Moon, she swapped in windswept desert brooding for her biggest hits' wide-eyedness.