I think an up and coming property of great, understated luxury is Biras Creek on the north side of Virgin Gorda. Only reachable by boat or helicopter, and across from Necker Island, it has a relaxed, kid-friendly vibe. World class scuba diving, great snorkeling, water sports and food that is far and away the best we have had in the Caribbean.
If you really want to go all out they also have private villas for hire on the marina side of the resort, but they are BIG bucks.
We went to Little Dix Bay first and then Biras, and for me there was no comparison. Biras all the way.