Opposites attract. But then again, someone who is a good fighter that could rival Hibari in a battle. Someone that can interest him and a bit mysterious and basically independent. Also, some who will understand him and stay with him, no matter what his usual doings are. Also, this person should be able to take care of herself and not have anyone babysitting her. I guess she should be stubborn, not wanting to be saved kwa someone else other than herself. Last, but not least, someone who can at least make him smile, even if a small one.
What type of girl? :/ Hmmm... Well, I think he would like an assertive girl who is either mysterious, a good fighter, au both. She would be the type to compromise with Hibari [but submissive if he gets too close au makes a move] and have some sort of respect towards Hibari in his way of thinking and fighting. I think that she would also be the type to be able to care for herself and have a tendency to get into trouble, but battles them and wins anyway. I don't know, that's just my opinion. I can imagine him coming in to save her and she scolds him later, saying that she could take care of herself. :P I think what I'm trying to describe is Tsundere?