For an all around nice experience that includes nice people, good dining, good water sports, I really enjoyed Barbados.

For beautiful sights, St. Lucia is very nice with the Pitons, and has hiking, etc. to go for. Certainly you will run into some poverty there if you get off the resorts.

Martinique is like a little piece of France plopped in the middle of the Caribbean, and is really beautiful with friendly locals. St. Barts is another really beautiful, friendly, and comfortable place, an easy ferry ride from St. Maarten.

For a great little place that is friendly, beautiful, has superb beaches, my favorite is a little island called Bequia a short ferry ride from St. Vincent. It is really small, though, so factor that in to your consideration.