I was scanning through and found this article.
credits: Female Magazine, Feb issue 2010, pg 88
The best neckline for your face
Hide your flaws and highlight your assets by choosing the best neckline for your face shape
the crew neck is high and round. It flatters those with lon
g necks and oval or triangle face shapes. Stay away from it if you have a round or square face shape as it will only enhance the roundness or squareish shape.
the boat neck is very open and slices across the collar bone. Wear this if you have a wide face. It will make your neck look longer and your body taller. Avoid if your face is narrow.
the turtle neck is unsuitable for most face types. Those with narrow faces and long necks should wear it, but those with round faces and short necks should stay away.
The V-shaped neckline flatters most face shapes. It is especially flattering for those with round or square faces as it elongates the face and gives it a narrower appearance.
The scooped neck is a deep, U shape and tends to flatter large woman with wide faces. It gives the illusion of balanced proportions and a longer neckline.