We got married in Vanuatu at Iririki. Absolutely loved our time there.
The weather was fantastic, the people are friendly, the water is clear and warm (perfect for snorkelling) and I would love to go back. I'm not sure if it is still the same (we were there in 2003), but Iririki is a kid free island/resort. It's more of a honeymooners accommodation, but from what I hear there are other great kid friendly places to stay.