In terms of "beauty" I would have to rate Trunk Bay as the most beautiful. It is like something from a post card.
The only negative was that before the first time I went I was excited about what people had said about the fantastic snorkeling. We went into the water but the snorkeling was underwhelming. There is a underwater "snorkel trail" with signs that direct you to different types of coral and other things. While interesting there wasn't really that much to see, compared to other parts of the Caribbean.