South Island...
Interisland ferry from Wellington to Picton takes you through Marlborough Sound, Queen Charlotte Sound
Marlborough vineyards
Nelson is a lovely city
Golden Bay; Abel Tasman National Park
Kaikoura whale watching (road/rail could be tricky after ecent earthquake)
Christchurch
Banks Peninsula/Akaroa, originally French territory, still has a lot of French influence. Beautiful scenery. Penguins. Fur seals. Dolphins
Glaciers - Fox or Franz-Joseph, free to walk to base of glacier, also guided walks
Mt Cook National park
Milford Sound + boat trip in large catamaran
Queenstown - loads of activities related to mountains, eg gondolas, walks fab views, paddle-ship trip on Lake Wakatipu, views of Remarkables Mts
little blue penguins and yellow-eyed penguins Oamaru Penguin Colony
Tranzalpine train from Greymouth-Christchurch, over Arthur's Pass