Ohhh...a fun question
I'll review each first...
Tarp- Great to have and can be used for many things.
Sunscreen- Won't Last. Also ,I could easily stay in the shade midday.
Toilet Paper- Won't last a week.
Pot- Useful for boiling things.
iPod- Useless to someone like me.
Hiking boots- Depends on the island. I'd definitely use them if I was on an island like in Cast away or 7 days, 6 nights.
Handsaw- Useful
Flare Gun- Limited- there's always the chance it would go unnoticed.
Inflatable Raft- It depends on the island and where it is like someone said.
Flashlight- Batteries won't last
Insect Repellent- it won't last
Hammock- great, especially in the tropics
Compass- Depends on the island and whether I'm able to get off the island. If it's a small island and the currents won't let me get far from the island, I may not have much use of it.
Mirror- More reliable than Flare gun, plus I could use it to start a fire.
Vitamins- It won't last
Water Purifier- Unless the island was full of tepid water sources, I could get by without. Plus, I can just boil the water.
Fishing Rod- Definitely useful, but it may depend on type of water.
Rope- It can be made, but it could be useful.
Hunting Rifle- First of all, chances are there are no large animals that one would shoot. Bullets would be wasted shooting rodents that react so quickly, all that.
5 Ounces of Weed- No
First Aid Kit- If I need one badly, I'm fucked anyway.
Tent- Nice, but not necessarily durable and stable long term
Knife- Nice to have
Matches- They won't last
Volleyball- No
My choices are....
Tarp, Handsaw, Pot and Mirror.
Rope, Hammock and fishing rod can be made and a knife can be fashioned from a rock.