Carrie Underwood

Only six months after winning the fourth season of American Idol in 2005, small-town Oklahoma girl Carrie Underwood suddenly became one of the biggest country-music artists in the world. Idol judge Simon Cowell predicted her massive success after a stunning performance of Heart's "Alone" on the show, and once Underwood had the chance to hit the studio, she delivered the hits. Some Hearts (Number Two, 2005), her debut album, remained on the Billboard Top 200 for more than two years — enough to help it sell more than 6 million copies. The record remained the best-selling female country album of 2005, 2006 and 2007 and was nominated for four Grammys — Underwood walked away with two trophies, for Best New Artist and Best Female Country Artist.

Less rockish than Kelly Clarkson (and less mawkish than Clay Aiken) Underwood's breakthrough came with the smartly crafted "Jesus, Take the Wheel" (Number 20, 2005), a ballad that showed off her Christian and country-pop appeal in equal measures. The seething done-me-wrong track "Before He Cheats" (Number Eight, 2007) was even more crossover-worthy: The song about karaoke bars and four-wheelers which was meant to be played in both earned her another Grammy win in 2008.

Underwood's follow-up, Carnival Ride (2007), debuted at Number One and found her once again working as many formats as possible, a feat perhaps best exemplified by the steel-pedal uplift of "So Small" (Number 17). Her cover of the Pretenders' "I'll Stand By You" — recorded for the American Idol charity show Idol Gives Back — also hit the Top 10. In May 2008, Garth Brooks inducted her into the Grand Ole Opry.