Good idea. My addition to the thread is
Auckland, NZ
I lived in this city for 5 months, left back in March. When I got to the country I didn't know anybody, by the time I left I was working as a bartender and had hundreds of friends.
Nightlife
Three main nightlife districts. Queen street, K road, and the viaduct. On Queen street you'll find most of the backpacker bars, K road is the "alternative" area of town, many gay bars, and the viaduct is where you'll find the higher end clubs. Most clubs are open until 7AM, and Queen street is packed all night on Friday and Saturday nights.
Hotels
I only stayed in a hotel for a few weeks when I first arrived, then I moved into an apartment. Most hotels in the city will have weekly rates, take advantage of this. Many hotels in and around Queen St. I recommend staying in the central business district, that way you'll be close to everything. I stayed at the Elliot Street Apartments/Hotel, it was pretty nice.
Transportation
Because the city is surrounded by the ocean, the airport is really far away from the city. Don't take a cab from the airport, take the Airbus
http://www.airbus.co.nz/home/ instead. This will take you directly to downtown Auckland.
Things to Do
Bungee jump off the Harbour bridge (a huge bridge that connects Auckland with the North Shore).
Have dinner at the Sky tower (
http://www.skycityauckland.co.nz/Attractions/Skytower.html). Last time I checked it was the tallest building in the southern hemisphere.
Jump off the sky tower.
Shopping
Queen Street has everything you'll need. If you are into high end fashion, check out High Street (the next street over from Queen St.)
I liked this city a lot, It's a great place to go during the winter months here in Canada. Temperatures in December and January were usually around 25 degrees, not too hot, especially compared to Australia. Really humid though.
If I have the chance to checkout NZ again, I'd definitely want to check out Queenstown on the South Island and do more exploring.