I don't know why but Aussies can get cheaper packages to ski in NZ than NZ'ers can. If you can get a package to Wanaka that includes Cardrona and Treble cone, then take it. Between the two areas you have a good vaiety of terrain, Cardrona is great or beginners and internediates, or getting your ski legs back. Popular with snow boarders who like man made pipes. Treble cone has lots of natural gullies so don't botherw ith man made pipes.
Queenstown is a true resort town, lots of bars and plenty of places to spend your money. Wanaka is more low key, more to my liking, but still plenty of party options if that is your thing.
Queenstown and Wanaka is only a one hour drive (but over a pass that can be icy) so you can always travel between the two.
From Oz you can fly direct to Queenstown which means less travelling time and more ski time.
NZ also has the club field option. Club fields are run by skiers, don't have the fancy facilities like snow groomers or chairlifts, but they do have less crowds and you can stay on the mountain. It is a very different experience that is a lot of fun. My favourite iswww.craigieburn.co.nz
Don't go to the club fields unless you are comfortable off piste, at least intermediate skier and are reasonably fit. Snow boaders can struggle with the rope tows and it can be very tiring, if you are left foot forward it is easier cause you are facing the rope tow. If you are right forward forward it can be very difficult. The reward is that there may not be many others on the mountain mid-week and you sometimes think you are on a heli-experience at $50 a day
This panaroama from the top of Treble Cone gives you an idea of the better scenery and slopes that we have in NZ compared to Oz.http://www.lakewanaka.co.nz/index.cf..._aspiring.html