3. Justin Guarini, ''Who's Lovin' You'' (season 1)
He's been reduced to an Idol punch line, thanks to his anemic record sales and a starring role in the wretched From Justin to Kelly, but watch the guy's seamless, self-assured audition again with fresh eyes. As Simon himself points out, it's a privilege to sit back and listen to undiscovered talent this terrific.

Justin Guarini's audition: Watch it on YouTube