The three things I would take is -
1. My collection of harry potter books but if each book equals one item then I would take my favorite book which HP:OOTP

2. My Husband - so I wouldn't get lonely

3. Suntan lotion so I wouldn't get burnt to crisp

I could hopefully assume that the island could provide food and water - if there was a fresh water stream on the island, I could drink from there. Being that the island is surrounded by the ocean, I could fish for food, maybe there would be wild animals to hunt. Of course I would have to make my own spear or weapon by using the trees.