A satellite phone, a GPS and some kind of dynamo charger to charge them if needed.
This sounds like cheating, but based on the lack of rules I think you win.
edit: If you want off the island that is.
Mora Bushcraft Black; Kindle w/ all my books; solar charger for the kindle. Good to go.
This is pretty much my list. Even if I was dropped off naked, I could eventually make clothes. Or just run around naked for a while. I'm assuming my wife doesn't count as a thing, because I would want her there too. If I had to count my wife as a thing, I would replace the knife and work on fashioning something with a shell or basalt or wood.
The bikini tour bus with all the ladies (think Dumb and Dumber), unlimited rum, and a nice beach house.
GPS, map, and sailboat. Not much of a beach person.
An insane amount of MREs, water purifier, and a survival book with pictures of naked women.
Hydro electric plant, a home, water purification system
What are you going to eat? Electricity bzzzcuits? Windoughs? Activated-carbonbons?
There's probably crabs on the island.