Feel the need to keep this going.
Pal nominated Ann Curry, who I happen to think has mainstream appeal. Anyhow, Ann's been wearing pullovers lately -- she's not really chesty, but a pullover hath power to flatter the most modest figure. Ann Curry in a pullover -- lemme at her!
All right, a serious contribution: GRETA GARBO. True, even a Garbo detractor can see her beauty, but she cultivated much strangeness nonetheless. She was cool, aloof, mildly haughty, world-weary, and probably preferred girlfriends (perhaps especially Marlene Dietrich?) to boyfriends, a living inverse of mainstream voluptuousness and the usual sexual hotness -- but I just caught her in Queen Christina, and WHAT A WOMEN. Thought I'd try an honorable mention.