I'm sorry I missed this message earlier. We saw so many areas on our trip...Christchurch, Dunedin, the Lake Tekapo region, Te Anau, the east coast. Perhaps my biggest highlight was visiting the glow worm caves at Lake Te Anau, very near the Fiordlands Park region.
I am happy to answer any specific questions you may have. We traveled from Japan via Taiwan and Sydney before arriving in Christchurch, so my flight/carrier recommendations may not be worth as much to you. Everything else is fair game!