The 'Idol' Idols

Christina Aguilera: Kevin Mazur/WireImage.com; Katharine McPhee: Fox; Kelly Clarkson: News International/WireImage.com

All About

American Idol

Katharine McPhee

ROLE MODEL Christina Aguilera

BAD INFLUENCE Kelly Clarkson

PROFESSIONAL PLAYBOOK With her well-trained voice and cover-girl looks, Katharine is probably the Idol contestant who's most likely to go platinum — as long as she doesn't try to follow in the footsteps of season 1 champ Clarkson. Maybe that's because the polished, power-ballad Kat who scored big with ''Someone to Watch Over Me'' and ''Since I Fell For You'' was a lot more convincing than the rocker-grlll version who emerged on ''Bringing Out the Elvis'' during country week. And anyhow, with Whitney on the sidelines and Mariah working more of an R&B vibe, somebody's got to keep Xtina on her toes (although perhaps not in the ''Dirrty'' leather chaps department).