I'm planning a trip to New Zealand and I'm not sure If I want to do just the north island, south island or both. I would be saving a good chunk of money if I did just one island. If I were to pick one island, I'm leaning towards the south because I've heard from a few people it's the only one worth doing. The problem is that I don't know when I'll ever be in this part of the world again. Is it worth shelling out extra money to do both islands, or should I just do one and save money for another trip? (I'm getting towards the end of a year long working holiday visa in Australia)