Best part of New Zealand, if you have the opportunity I would do an overnight boat cruise. The place is amazing with the walls so high and there are so many waterfalls

The most famous track is the Milford Track often called the finest walk in the world. The trail winds through a beautiful landscape of mountains and beautiful temperate rainforest in the Fiordland National Park. Several tour companies in Queenstown offers guided hikes along the Milford Track as a package 5 day and 4 night. If you have time and are physically fit, I seriously recommend this hike. The sight of the towering snow capped mountains, gorges of solid granite, blue lakes and spooky mossy forests simply enchanting.
http://www.travelaustralia360.com/milford-track-new-zealand.html

The temperature here is quite cold and it snows with strong winds and heavy rains. These occur at any time of the year. There is rain that averages almost every other day during the hiking season. Although the most amazing thing about these places are the waterfalls. These are in plenty and they cascade over each other lie beautiful silver threads. Most tourists take boat tours, but hiking, backpacking and canoeing are also pursued.
http://www.australiavoyage.net/milford-trail-in-new-zealand.html

Very majestic. I liked the combination between the high mountains and the dark water. The waterfalls everywhere are amazing. I went even diving in that cold water and that was not worth it... It's pitch black because you dive through a 2-3m freshwater layer and underneath there is almost no light. You will see few crayfish and black coral and sea stars... I think a boats trip just to enjoy the beauty of Milford Sound would make a better choice....

When you get a first glimpse of Milford Sound, just after getting on the cruise, you know that this is the closest you can get to divinity... The fiord, in all its beauty, is the finest natural creation, with its splendid waterfalls...
In Rudyard Kipling's words, Milford Sound is the Eighth Wonder of the World ....