1. Kelly Clarkson, "Respect"
Before Kelly Clarkson became a pop juggernaut, she was a bubbly Texan who said "cool beans" a hundred times an hour, and charmed the frosty tips off Brian Dunkleman. With "Respect," she proved she was a seriously salable artist and a soulful chick, to boot.
2. Kimberley Locke "Over the Rainbow"
When you're forging through the semifinals, you're forced to sing every bombastic ballad under the sun in order to be noticed. That wasn't hard for Kimberley Locke; the "Eighth World Wonder" chanteuse vaulted to the fore with her rendition of cinema's biggest tune ever.
3. Carrie Underwood "Because You Loved Me"
Now hear this, Nigel Lythgoe: The semifinals afford quality contestants the chance to discover their niche in the competition. After performing hits by Tiffany (?!) and Janis Joplin in the weeks prior, Carrie Underwood rounded out her semifinal run with a big Jo Dee Messina ballad. She'd later stick to country and establish herself as American Idol's queen supreme, and this was her first moment as a criticism-proof balladeer.
4. Chris Daughtry, "Hemorrhege (in my Hands)"
Chris Daughtry, my favorite rock singer with parabolic sideburns, foreshadowed his post-show success with this searing, radio-ready version of Fuel's hematoma of passion.
5. Elliott Yamin, "Moody's Mood for Love"
Also, Lythgoe: The semifinals rule because contestants often pick the dorkiest songs imaginable. Remember last year when Didi Benami hit us with that bleat-y version of "Lean on Me"? Or when human-size sea monkey Alex Lambert tried on James Morrison's "Everybody Knows"? Well, the dorkiest-of-dorky song choices came in the form of James Moody's "Moody's Mood for Love," and Elliott Yamin sang the hell out of it. It's the kind of performance that reminds you Idol is totally uncool -- but also fabulous.
6. Melinda Doolittle, "My Funny Valentine"
You can have your Fantasias and Adam Lamberts, but to my ears, the greatest vocalist in the history of American Idol is Melinda Doolittle. And better yet, its greatest vocal performance is Melinda Doolittle's semifinal-jumpstarting rendition of "My Funny Valentine." So smooth! So unpretentious! Melinda radiated brilliance, and as we often find with reality competitions, being consistently great is often cause to be voted out before your time. (RIP, Brandy and Maksim Chmerkovskiy.)
7. Antonella Barba, "I Don't Want to Miss a Thing"
Now wait: I said incredible performances, not great. A big reason Idol's semifinal rounds are indispensable is because they separate the champs from the chumps; the producers' pets who sneak through the auditions with their adorable cheekbones and dog voices are exposed for the shiny shams they are. Antonella Barba exemplifies this (eminently watchable) trend -- and she leads an army that includes Tim Urban, Camile Valesco, and the inimitable Danny Noriega.
8. Jason Castro, "Hallelujah"
He may have only gone on to play the ukulele at Jason Mesnick and Molly Melaney's Bachelor wedding, but Jason Castro proved in the semifinals that his talents exceeded an ability to grow 36-inch dreadlocks. You will note that his version of "Hallelujah" is better than the aforementioned Tim Urban's.
9. Allison Iraheta, "Alone"
But my favorite part of Idol's semifinals is how they allow voters to judge the heretofore un-aired contestants for their merits. Throughout the audition process in season eight, we'd seen nothing of Allison Iraheta, but when it came time for the burgundy-coiffed teen to perform "Alone" during that year's bizarre semifinal format, she launched ahead of the pack and became the season's indisputably best female vocalist.
10. Katelyn Epperly, "The Scientist"
Every year, Idol semifinalists are voted out before their time. In season nine, the two shafted talents were Lilly Scott and chirpy Des Moines native Katelyn Epperly. Now, all we have left of these warblers is their "three-week wonder" mystique and their solid musical performances. Epperly's performance of "The Scientist" was one of the best of the season -- even if the panel didn't see it that way. Prepare yourself for one of Ellen DeGeneres's most cutting criticisms: "It was so slow. And it was way too slow."