Turks and Caicos
Tranquil turquoise water atop nearly white sandy beaches all over the Turks and Caicos. Sapodilla Bay, Chalk Sound, and Grace Bay were all beautiful, although Chalk Sound National Park is particularly tranquil at the water's edge. For warm water and fine sand, this is pretty hard to argue with! More time to lay around Grace Bay would have been nice...
Sadly no time to get further than Providenciales-- getting to Grand Turk is an inter-island flight, while the other islands are a ferry ride away. And the airport is... well... best described as crowded but air conditioned. Although even the views from the air are beautiful, so more time in airplanes may not actually be a bad thing if you want to see the other islands.
Lucked out with upgrades on all of my flights, so despite being in a lot of airplanes, I can't complain too much. Considering almost everything has to be flown or shipped in, even bad airplane food helps to reduce my environmental impact on the islands??