I was originally planning a trip to New Caledonia for my aniversary in October. After much research, my wife nixed the idea. Apparently there are numerous posinous snakes there on both land and in the water. I think my wife would drown is she saw one while snorkling. This may not be a consideration for most but it was enough for us.
I ended up booking a week in Moorea and a week in Bora Bora.