Most Helpful Guy
It always depends on the guy and how the rest of the girl looks. One style can fit perfectly on one girl but not so good on another. So there is no single correct answer that will fit best for all girls. You need to experiment and find which style you like most on yourself.
Most Helpful Girl
Honestly depends on the guy. So do what you feel makes you look better, and you're happiness with yourself will be ultimately more important than a guys opinion. Don't let men rule your world.