If you're really looking to get away from it all (and avoid the crowds), and you don't mind a long flight to do it, check out Chumbe Island off the coast of the island nation of Zanzibar (yup, that's in Africa, folks). The secluded vacation destination made the top of the Travel Channel's of places to truly escape civilization. They describe it as a "lush coral gem featuring a pristine jungle, an old, unmanned 60-foot lighthouse (a great place to watch the sunset) and often not another soul on the island apart from yourself and a ranger."
Don't look for too much luxury if you're going to stay on Chumbe Island though, as most of the fancy accommodations are back on the main island, but there's plenty of things to do and see. Chumbe Island features some of the best snorkeling on the west African coast, the low tides expose the exotic coral, and there's plenty of interesting beach to wander along as well.