First don't buy from a nz retail store unless you like getting ripped off
If you want a quality phone go for htc or samsung. The Galaxy S or Desire HD are both great and can be had for around $450, but I would spend the extra $100 and get something like the Senstation, dual core cpu makes it much more future proof, but there is the Optimus 2x for around $450 if you are happy to sacrifice some quality for lower price.
If you are with Telecom watch out you get the right version wcdma 850/2100 or you want get any service out side main centers and most phones are 900/2100mhz that are for Vodafone/2degrees.
The Optimus Black looks ok but it's screen and camera is about all it has going for it and come with an old version of Andriod 2.2 but is upgradable to 2.3. It is said to have poor battery life, worst than many more powerful dual core phones and lg have a terrible ui. LG might be cheap but there is a reason why. HTC Samsung and Motorola all make much better phones that don't cost much more.