Maui, Kawaii, or Oahu. Hands-down, Hawaii is known as paradise for a reason. I spent a week on Maui, and I can tell you that it didn't matter if I was doing something touristy or trying to be a 'local' (stretching that term there), I had fun, it was beautiful, and I will never forget it although it's been about ten years. I still remember the feel of the sand, unlike anywhere else I've ever been, as it went into my sandals, the colors of the water, snorkeling at Molokini off of Maui and seeing the fish, and the turtles! It was heavenly.
And did I mention it has a rainforest on one side of it? Absolutely amazing the variety of terrain on the one little island that you can drive around in less than a day.