If choosing between Thailand etc and a South Pacific island, I'd choose the South Pacific. So warm and friendly and relaxed. Maybe not as many historical things to see, but if you just want to chill out, then it's perfect. Lie on a beach, go snorkelling, eat, drink, lie in a hammock with a drink., lie in the pool with a drink..... If you want history, temples etc, then South East Asia has more of that but they also have more people, traffic and ways to get ripped off.

Fiji and Vanuatu etc also have no death penalty, which I always think is a bonus (but then I'm a paranoid traveller).