This is without a drastic amount of gym and CAS type of work. This is not asking who's pretty after you change their style. I'm asking who do you find to be a pretty premade Sim, without the use of a makeover.
Anyways here's my list of premade townies, who I find are super pretty without the use of the gym and CAS:
-Pauline Wan
-Bebe Hart
-Sandi French (has aged with really nice genes a few times)
-Claire Ursine's unborn baby (though other people's versions turn out rather ugly and deformed, mine turned out really pretty)
-Morgana Wolff (she looks exactly like Steve Tyler's daughter, Liv Tyler)
-Bella Bachelor ages up really pretty, with deep olive skin and green eyes
-Lisa Bunch and her little sister Darlene
-Nancy Landgraab
-Kaylynn Langerak ages up pretty too, as she inherits her mom's dark hair, brown eyes, and fair olive skin, I can't spell her mom's name though.
-Zelda Mae (I personally don't think her makeup is that bad. I do my makeup that way in RL)
-Justine Keaton
-Monika Morris
-Ruby Broke
-Susie Broke (has aged in to an attractive teen)
-Betty Newbie (as in her teen form)
I find it odd to find my male sims to be attractive, since they're virtual people.