20. CARLY SMITHSON, ''Superstar'' (Season 7)
She'd been knocked around for weeks by Simon Cowell, but Sir Andrew Lloyd Webber turned that all around, insisting the Irish songbird switch from what he described as the ''girly'' ballad ''All I Ask of You'' to the raucous, rousing title track from Jesus Christ Superstar. ''You've got to go for a song you can inhabit!'' the guest mentor exclaimed, and indeed, Carly did exactly that, detonating her nerves and delivering a blistering vocal that had Simon smiling, Paula on her feet, and Carly's fan base finally getting the performance they'd been expecting all season long.
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We revisit the classic performances all contestants try to measure up to -- see which of your faves make the cut