There are a million ways to judge an American Idol - who wins the competition, who sells more albums, or who goes on to win an Academy Award - but, at it's most basic, A.I. is a singing competition, which means an Idol is only as good as his or her best performance. We're taking a look at the very best performances from the last six seasons of American Idol. See if you agree with us!
#10 A.I. Performance - Chris Daughtry (I Walk the Line)
This season five rocker brought down the house when he covered the Johnny Cash song I Walk the Line. Chris was given serious props from the judges for giving the classic tune his own twist and staying true to his alternative rock roots.#9 A.I Performance - Bo Bice (Spinning Wheel)
Bo Bice boosted his classic rock cred when he sang the Blood, Sweat and Tears song Spinning Wheel in season four. He nailed the vocals - as well as some serious Stephen Tyler-style mic dancing. The judges went crazy for the performance, and even grumpy old Simon said it looked like Bo had been "doing it for 20 years."#8. A.I. Performance - Diana DeGarmo (Don't Cry Out Loud)
Diana DeGarmo may have been the third season runner up, but her performance of the '70s Melissa Manchester hit Don't Cry Out Loud was a winner. Diana's stage presence, power-house vocals and old-soul gained her much love from the judges and the audience.#7. A.I. Performance - Melinda Doolittle (I've Got Rhythm)
Season six's Melinda Doolittle gave a vocals master-class when she sang the classic tune I've Got Rhythm. Even Simon had to admit that he can never find anything bad to say about Melinda. Who could ask for anything more?#6. A.I. Performance - Clay Aiken (Build Me Up Buttercup)
Clay Aiken won over fans - and the judges - during his season two performance of Build Me Up Buttercup. While Simon pointed out that no one had any idea what the song lyrics meant, he couldn't fault Clay's rendition of The Foundations song.Related Stories: