Fiji, Cook Islands, Tahiti or Samoa?

Please help me out!
I'm so confused about where to go. I'm leaving aussie/NZ in end of july and will visit one of these places, but I'm so insecure in where to go!
I've been to Fiji once before (beach house and robinson crusoe isl.) and loved it. I know there is a lot of other places to go in Fiji as well, but somehow it's a bit funny to visit a new countries as well, but not a must.
I love snorkelling and diving, but also all sort of activities. I'm not thinking of staying on the beach all day.
It will probably be for about two weeks and on a backpacker budget.

Any suggestions?

I'm 25 years old.

Lucky you!

Start by reading the FAQs in this branch, then get back with less general questions.