Especially if you buy a full fair ticket, Virgin Blue could be the wrong choice. That airline will not issue you a refund on any ticket sold at any price (even if you bought the premium priced ticket). The best you can get out of them is a lousy voucher. If you are a foreign visitor from another continent, a voucher on Virgin's South Pacific airline is not likely to prove so useful, is it?
Anyway, I have found Jet Star very accommodating. A ticket refund is simple to arrange, but only if you paid full fare, then they only penalize you $30.00. I also like their Southeast Asia partner, Jet Star Asia.