Sorry I am just laughing my head off at someone saying that all of the north island of NZ looks like Dorset 
And nothing to do here? I have lived in NZ for quite a few years, on both islands, and I have not run out of places to visit yet. And I don't even do all the mad adventure stuff. It's a pretty varied country.
I miss visiting a lot of the European cities people have mentioned though, I love history, particularly medieval and there is definitely none of that here - Rome is number 1 in my places to go back to, it's just so fascinating, wandering around you come across so many different things. I went as part of my ancient history A level course so maybe that helped as we went off the beaten track to places like Ostia as well.
I grew up camping in the New Forest, beautiful place. Lots of forest to explore and great cycling. Can't comment on how busy it is now though as haven't been back for about 15 years.
I have to say the CBD of Auckland is a bit underwhelming as there is not much there to do apart from the sky tower and the theatre, but it is mainly offices and food malls plus the university. You really need a car to get out and explore, it's the suburbs and islands around that are beautiful, not the centre.