We have been to Fiji, NZ, Malaysia and Europe with the kids and just got back a couple of days ago from Singapore. It depends what you are after.

Singapore was fantastic - so many things to do - The Zoo, Universal Studios, Legoland in Malaysia (a day trip away), Singapore Flyer. But it wasn't a relaxing holiday - we were on the go non stop and the humidity slowed us down a bit. Would certainly go back again.

A couple of years ago we went to Kota Kinabulu in Sabah, Malaysia. Flights weren't long, resort was great and kid friendly and it was a nice relaxed holiday. Again there are still things to do eg zoo, another day trip out to see the orang-u-tans in their natural habitat. We hung by the pool a lot which was what we needed. Fiji was much the same. Not much shopping in KK or Fiji whereas you are spoilt for choice in Singapore

Campervanning around NZ is great fun. Kids loved it, especially the South Island - but you need more then a week or two to do that. Unless you flew straight into somewhere like Queenstown and spent a week there?

Hope that helps.