I would choose Wireless laptop, but that wouldn't really work in the middle of nowhere...
1: My best friend 2: Water 3: My Bible
That way I could die a fun, friendly death. I'm hopeless using a compass OR boat. And a map would be useless on a desert island. And I could quench my thirst, at least, until I run out of water.
But in the long run, I'm hoping I never get stuck on a desert island. If it were four things, I'd add Mad Libs. xD