Been to South Africa (4 years), New Caledonia (4 months), Australia (2 weeks), Carribean Islands - Martinique (more than 12 times), Israel (Jerusalem only, 2 months).
For a whole gap year, don't go in the Carribeans. You'll run out of things to do, when you're not blocked in the house with no internet because of a cyclone.
Israel seems like a very poor choice at the moment.
Australia seems like a decent option, since you can visit New Zealand and other close countries, while being able to work there. There's Uluru and stuff for all the "earth" people, and some nice bitches beaches for the "water" people.
South Africa was entertaining. And i've got some very sweet memories of that place. As well as a lot of gruesome ones with people being killed in their car while riding in town and (stupidly) stopping at a traffic light. Got robbed twice, and killed our car (4x4) on the typical south african road, while it was raining. If you like to live dangerously, why not. But seems like a gamble.
Good luck for your Gap Year, lots of planning needed !
