I need help deciding where to go on vacation?

well me and my husband are trying to book a vacation for october for our anniversary. I have been looking at St. Thomas (because no passport is needed and snorkeling is amazing there) I have also been looking at Aruba and Grand Cayman Island. Anyone who as been to these places please let me know your thoughts of them or if you have been somewhere else and feel like it would be a great trip feel free to let me know. I am just looking for somewhere warm, clear oceans, great snorkeling, and not ridiculously overpriced.