Turkish Delight. (or this one flavour at a now-closed local ice-cream shop, which was called Turkish Delight, but I don't think it really tasted of actual Turkish Delight)
That, or Mint Choc Chip.
Because, if I do happen to be stranded on an island (and I'm presuming a hot desert island), if the ice-cream melts or what-have you, I can drink the cream, and be left with the solid chocolate.
Which is high in sugars. Could sustain me for a little bit, with some rationing.
That and Mint Choc Chip is lovely.