Zoe is probably the smartest chick in the game.
Beatrice?
She would be my gf, btw, people say she's ugly, but she just needs to take better care of herself, get rid of the glasses and change her freaking hairdo. Same with Angie. The only girl who is truly ugly is Eunice.
But considering the girls as they truly are, I don't know, I think it would be Zoe. She's dull to me, but she's the most dateable girl there. The others may be pretty, but their personalities are just despicable.
Honorable mention to Delilah, the good siamese twin. She's one of the prettiest girls in the game, shame Rockstar made her a freak. If she was normal and a student at Bullworth, she would definitely be my Bully girlfriend.