Reese Witherspoon
The teenager with a critic's favorite first kiss who grew into the 2000s' defining star. Southern charm and comic precision built through the '90s—Fear, Freeway, Election—but then Legally Blonde detonated, and she owned the decade. Walk the Line proved she could do Oscar-worthy dramatic work. Married and divorced Ryan Phillippe in a trajectory as public as her career was inescapable.