I dont know what New Zealand dollars are in USD but that doesnt really matter. Basically get what sounds the best for the money. Also consider what you are getting the amp for.
Are you playing a lot of shows, or are you just fooling around in the garage? If you play a lot of shows, I would suggest to invest in something that may be more expensive, but is worth it in sound, portability, and that you will not need to step up to something bigger in a year or two.
I'll tell you all a story now, so sit and relax. Go make a sandwich or something
When I first started playing, the amp I used was a S*itty Ibanez POS amp. It was the worst thing I had ever heard. I eventually got a Crate BX100 because my drummer plays insanely loud, and you could yell louder than the Ibanez amp could go. Well, the Crate was doing fine until my drummer started playing louder, and we started play a few little shows at school and a park. (mind you it was good for use in the School Jazz Band) So I saved up some money and went and ordered a Carvin R600 Head with Avatar B210 and B115 cabs. (I highly reccomend these amp and speakers, but if you are looking for max power from the amp, order the speaker in 8Ohm; I ordered them in 4Ohm and am only running 275watts per cab.) Anyway, I am in the process of selling my Crate amp to my drummer (i keep forgetting to give him his DVD movie back) and I am very happy.
So the bottom line is: Get what sounds good, and what will be the most practical for you. I feel I kinda wasted the money on the Crate because It didnt last me long (only about a year). Now I know I will keep the Carvin/Avatar rig FOREVER!!!
(sorry for the long post)
~PHIL~