Hi Lindsey,
No worries, glad it all helps

No one would blame you at all for crossing Christchurch off your list. It will be a great city again one day (actually I've just posted a new blog post on NZ Raw because a draft of the rebuild plan has just been released this afternoon) but in the mean time there's going to be a whole heap of building work that will include arguments, finger pointing and stress!
I've considered moving to Auckland. I'm deep in the Internet industry in NZ and Auckland is the place to be for that as that's where all the modern business is.
It gets a bit of flack from the rest of New Zealand as:
- it's the most expensive place to buy or rent a house
- it has a high immigrant population (although I guess we'd class ourselves in that area!)
- the traffic can be pretty bad
But having said that, it's also loved by many and you can have a good quality of life there. I haven't spent much time there but when I did, I was quite impressed. Head back to that blog and search for 'auckland city not that bad' and you'll see a short post I wrote in 2009 with some photos.
I don't know the Hawkes Bay I'm afraid but I've heard nice things! That probably won't help you that much!
One thing's for sure - there should be plenty of work for Civil Engineers right now. Although there's a chance that New Zealand's building and road development efforts will be focused in Christchurch to the extent that the rest of NZ might be put on hold, but I'm sure there will be a lot of remote work based in Auckland so you should be sweet there.
For the salary that you mentioned and the quality of life you're interested in, you should be totally fine. My wife and I have a combined salary of far less than that and we basically do all of those things you mentioned! We have a weekly mortgage of just under $400, two cars and a dog and we still manage to eat well and get out for a meal and a holiday from time to time.
Auckland will be more expensive than Christchurch - what you'll get for a $400 rental in Auckland won't be as impressive as a $400 rental anywhere on the south island, but I doubt you'll have too many problems finding somewhere nice.
The place to look is trademe.co.nz. They have heaps of rental listings as well as cars for sale - it's the number one viewed website in NZ so can be a pretty good indicator of fair prices.
Let me know if you have any more questions
Mark
P.S. I'm not sure but for teaching I think you would have to complete an NZ-based certificate to supplement your own experience and qualifications - NZ is funny about having their own qualifications for local jobs. You shouldn't have too many problems finding work if you chose to though - we have a bit of a 'brain drain'. People study here and then end up moving to Australia where the income is generally higher.
Oh also - the weather here can get pretty cold in the winter

I'd say it's quite like the UK but better. The top of the north island obviously gets the warmer climate and temperatures of the 30 degree mark aren't all that unusual in the height of summer up there. However, it's winter now and it's getting down to about -2 at night and then around 10 to 15 degrees during the day in Christchurch at the moment.
P.P.S sorry just saw your questions in your post - am I glad I moved here from the UK? Absolutely. I do love it here. I moved here from Liverpool specifically because I was sick of the racist locals and the crime (and that was long before the riots of the last week!). New Zealand does have crime - probably best to stay clear of South Auckland - and there's still racism against Maoris as well as our large asian population, but for the most part it's much better than the UK.
The scenery can be incredible - you can go from geothermal hot pools, sandy beaches and areas of forest that are almost like rainforests to snow-capped mountains, glaciers and emerald lakes. Pretty awesome. The way of life is also more laid back that the UK - no one cares about money here as much as they do in the UK. No one walks around in CK jeans or has 'armani' written across their jerseys. There isn't the same traditional pub culture that there is in the UK - that's one of the main things I miss - but there are plenty of smart modern bars and restaurants and Auckland in particular has a big coffee/cafe culture.
Used car prices are a bit steeper than the UK and are actually set to go up next year as import laws are changing, but you'll find car insurance ridiculously cheap!
For some New Zealand photos, check out my Flickr account. It's Flickr dot com and then slash photos slash marklincoln (I need to get my post count up so I can post URLs!)