Diving New Zealand South Island

Studying abroad in New Zealand. Which is the better school location?
I have decided 100% on NZ, but I just cant decide which school to go to. I am deciding based on location because I am going there basically for traveling. I am really interested in the outdoors and the scenery. I am not necessarily going to do the adventurous sky diving and bungee jumping type things but I do want to be able to have the oppertunity to be able to do these things. I really really really want to see the scenery though. I know the south island has more to offer when it comes to scenery, but I am a little reluctant because I would rather have the warmer weather of the north island. I really love the beach and would love to have one close by. I would really like to be somewhere with a night life too, somewhere where I would not have to travel a lot to go out at night. (I’m demanding, I know haha)
My choices of places are Auckland, Wellington, Christchurch, or Dunedin.
PLEASE HELP!
I am a strong fan of Dunedin/Otago.
I googled the question and got a list of these schools which have interesting looking programmes for international students within that region:
http://www.bayfield-high.school.nz/index.cfm?content=international
http://catlins.school.nz/international.htm
http://www.internationaleducationmedia.com/study/obhs.htm
First Sky Dive – South Island, New Zealand