it's funny you know. I've lived here my whole life, and I can never think of anything to suggest for people to go see. I thnk i take all our cool stuff for granted.
That said, when I go for a trip away, I'm always like WOW! I forgot how cool this country is. Definately check out central otago, and the west coast of the south island. Hamner springs with the hot pools are a nice spot too. If you get your jollies on earthquake damage, then come to christchurch. lol Kaikoura is nice too. I'm crap at giving advice though. You'd probably like stuff that I take for granted.