Fiji

lucky you...tahiti no rain there in the summer

Most of the places mentioned in the other answers are not islands but countries. Vanuatu is not an island, Samoa is not an island, Tonga is not an island, Cook Islands are not one island and Fiji is not an island; all these places are island groups..Also answers are very touristy, i.e. fire dance is not a Fijian tradition but was invented for tourist entertainement. The few islands mentioned are standard tourist locations - Easter I., Bora Bora etc I have quite enjoyed American Samoa, I wonder why Kim W has a grudge against it. Vanuatu is fine if you are not a local women, so is Fiji if you are not a poor Indian Fijian working rented land.. For just a week, try Nauru, the smallest republic in the world - less than half the size of San Marino. Or, if you only have a week, maybe don't go..

Vanatu!

SAMOA without a doubt! (Not American Samoa though)

Vanuatu. I lived with a guy from Vanuaut for 3 months and he really sold it. Its apparently the happiest place on the earth, or at least generally agreed to be the happiest place on earth

I highly recommend you Fiji! It is truly a paradise over 330 islands invite to all you can think of: beautiful palm trees, snorkeling in crystal clear water, scuba diving in the most colorful reefs, magical jungles with waterfalls and amazing people and their fire dances... It is still my No1 of all times :) Otherwise Palau in Micronesia is quite nice especially for scuba diving and kayaking. It is very untouched and natural... and the water is so clear you can see to the bottom of the ocean!

Easter Island is awesome, but no so practical from OZ unless you're going all the way across the South America. So....my current rankings are 1 - vanuatu (do a multi-day hike to a live volcano!), 2 - Cook Islands - paradise! 3 - New Caledonia, relaxation, snorkelling but expensive and 4 - Tonga... let me know which one you choose Henryk as I'll be going in November.

I am happy that you asked:do not think twice and take the flight or cruse to the Easter Island.Maybe one week will seem a little bit too much but from my experience(this February)I could have stayed more than the original four days.In the first days you only see this very strange island but in the next days you begin to feel it.It is wonderful and it is a unique experience.Highly recomanded.

bora bora. theres ferries to nearby tahiti and moorea. so u can see places in that week :)

oh wow, wish i cud go there, but it's way too far to go for just a week mate.. :/

I recommend Easter Island. It's probably cheaper to get to other islands for you, but if you can swing a deal or don't mind a little extra for the flight, a week on Easter Island is great.