Pretty much any girl that's attractive, but doesn't act like a fucking snooty princess.
As for a girl I was gonna have kids with, I seriously would be looking for a decent height (5'6"-5'9"), attractive, with long muscle bellies and is athletic.
I want my kids to come out looking good and not have to worry about being "hardgainers". Actually, that could never happen cuz they'd be getting my geneitcs too, but I want to make sure the girls got solid genetics before having kids. Maybe that's corny, but that's for real. I seriously would think about that if I was contemplating having kids with a girl.