its fits her better:)

^Agree. Rosalie Cullen just sounds weird.

I used to get sooo angry when people said, "Rosalie Cullen". xD

To me, it was just that Rosalie's last name should be very obvious info.

in the movies though she is rosalie cullen. on all the promotion they changed it to cullen and in the soundbite interview with nikki she is refered to as rosalie cullen, even by nikki herself at one point. so it is pretty understandable why people who watched the movies before they read the book would call her cullen.