I know that so many people did not or do not like Breaking Dawn, but I honestly love it! I love where Stephenie went with the storyline and her characters--I'm now even used to the name Renesmee.
That being said it is hard to pick a favorite part, but for the sake of the question, I think I would have to say meeting all the new vampires and the Bella using her power to save the day (again).
Oh--and the last page where she is able to allow Edward to see inside her mind--LOVED that!