Jane, Jane, Jane, Jane, Jane!
Why is there always some nerd that mentions Mulan, but everybody always forgets about Jane? Not only is the person in charge of drawing her clearly the best at knowing how to make an animated chick look hot, it's the psychology and motivation behind her decisions that makes her the most attractive at all to me. Sure the man who lives with apes his hot, but I am absolutely certain that what attracted her to him was the fact that because of the context at which he was raised, and given his entire lack of experience with what the fairer sex entails, Jane might as well be a goddess to this man. She's a smart, civilized woman, so it's not like these facts are something she wouldn't be aware of. Her only two choices in the matter would be to either acknowledge it consciously, or accept it subconsciously. (Also, even if Tarzan had discovered how masturbation works entirely on his own, he can't really get hard if the only thing he can picture in his mind's eye is that a gorilla chick that sounds just like rosie o'donnel)
She doesn't love him personally, as much as she loves the idea of being worshiped by him personally. She clearly has a god complex, and that is really what seals the deal for me. (And don't try and give me any crap about how Jane isn't technically a princess. If Jane doesn't count, then there is absolutely no way Mulan counts either!)
Also, I can imagine some people preferring Ariel precisely because of the bottom half. Remember that Mermaids are, despite breathing water exclusively, still closer to mammals than actual fish. It wouldn't be like doing it with a fish, as much as it would be like doing it with a dolphin. There is probably a large subset of people that think the only thing imaginable that could be better than doing it with a dolphin, is doing it with a dolphin that also has boobs.