NZ is a great place just to visit generally and in August there is usually a plentiful supply of the white stuff. If you are taking your Fiance then Queenstown is the place to stay as there is heaps to keep her occupied with whilst you hit the mountains. You have 4 resorts with 1 and a half hours drive. Note that there is no on mountain accom so either a hire car or catch a bus is the way up the slopes. Breathtaking scenery however so not a problem. You can also do plenty of other adrenaline fueled activities there. They also have heliskining, snowkating and splitboarding tours from Wanaka and Queenstown.
I have heard good things about Chile and would like to try sometime but it is expensive for me to get there both from Russia or from Australia when I'm there.