Fiji 10 nights

Myself and a girlfriend are planning a trip to Fiji in September. We were initially planning to stay at the Sheraton in Nadi however it was recommended that we should stay at one of the islands. Can someone recommend an island. We are two girls travelling and want to go to diving (I'm a beginner but my friend is certified). We want somewhere chilled with good nightlife/other young single people.

I don't remember seeing too many young singles at the Sheraton. Probably too expensive.

Dont Stay at the Sheriton in Nadi...It is really Boring. we had 5 nights there and nearly went troppo...We then had a week on Mallolo Island ..That was great and we did heaps of snorkelling.....Have Fun...