I will be voting for (and why)
However I/S has memed me into posting my reasons. I've typed this out in Facebook threads several times recently so it should go here as well.
Party Vote - Greens. Not just because I generally agree with their policies but because NZ won't get better government until we as a country finally break loose from the idea of two-party, adversarial politics, and that is going to take a 3rd party gaining enough support to form a coalition of equals with either National or Labour. It won't happen this election or next, but the Greens are the best placed to get there eventually (and so it will probably be with Labour).
So in a way this is a tactical vote with a long-term outcome in mind.
Electorate Vote - I'm in Wigram, and I had hoped that with Anderton's retirement there would be an actual contest for the electorate vote this year rather than it reverting to a safe Labour seat. Alas Jim went and anointed the Labour candidate his preferred successor and I haven't seen anyone even trying to mount a challenge for the electorate vote.
I attended a "Political Roast" at the Uni a month or so ago and had some opportunity to assess the National and Green options there. I think National's Sam Collins has some promise especially if he stops quoting economic philosophers from early last century and updates his thinking based on the more recent evidence, but it was the Greens' Richard Wesley who really impressed and took the initiative to respond to questions several times when the other members of the panel just sat there looking uncomfortable. So I'll give him and the Greens my electorate vote as well.
Referendum - Voting to keep MMP of course. It is the most representative system by a country mile, even with the distortions in the way it is currently implemented. I can't see the promised review actually making it worse.
For the second question I'll vote for my next-best option, STV. There is an argument that people should tactically vote for FPP to make sure the run off is between MMP and the almost-certain-to-be-rejected FPP but I can't accept that on two levels
1. I can not honestly answer the referendum question - "If New Zealand were to change to another voting system, which voting system would you choose?" - with FPP.
2. The second question is ironically an FPP ballot. If the second referendum happens and as seems likely FPP is the other option then I want it to carry forward as little endorsement from this referendum as possible, and that is achieved by having it "win" with as small a % of the vote as possible (in the process highlighting the unfairness of FPP).
I'm pretty sure given my group of friends that everyone (NZ & diaspora) is planning to vote and has given who to vote for due thought. Some have even voted early (goodonya!). If you are waiting to vote on Saturday, please don't get lazy. The polling places open at 9 - get out and vote early. Arrange a voting buddy - flatmate or friend - it works just as well as it does for exercise or study. If you don't really see any of the parties talking about anything that piques your self interest right now then think about what effect their policies might have on individual family or friends that you care about, or on where you plan to be or what country you would like to live in in 3 or 6 or 9 years time.
I didn't really start to grok the bigger picture and really become interested in politics and government until I was in my 30s. I don't think I really wasted any votes in that time, but I certainly regret not giving them more thought.