Hi,
I agree with MB and I would take the opportunity to travel round for a few weeks before looking to settle somewhere.
There are advantages of both Islands. I love the South Island and would love to live in Nelson for example but the job opportunities and wages aren't as great as some of the other cities.
We've been in Wellington for almost a year now and before we moved out here I was adamant I wouldnt live in another big city and defo not Wellington. I didnt take to it when we visited on holiday and kept this image that it wasnt that great. Now I love it. I dont think we'll be here forever but certainly long enough to get some savings behind us then perhaps we'll head up North a bit more.
It's really difficult to decide on where to settle until you're here.
Another good idea is to get on the web and have a look at vacancies in your prefession.
www.trademe.co.nz and
SEEK - New Zealand's no. 1 jobs, employment, career and recruitment site will give you a good idea on what's on offer and where on the job front.