First, I think it's your responsibility to read up on party's policies and vote according to those policies.
Second, there's a general perception that it is your duty to vote.
I disagree. I think that you have a responsibility to vote; if you forego this responsibility, you also forego any complaining rights about whatever government ends up in power or any governmental policies you don't agree with. If you don't vote, you forego that right to complain.
On the radio recently, they were asking "undecided" voters to call and say what they were thinking. The first girl who rang up said she knew it was her duty to vote, and she was going to, but she couldn't decide because "Helen Clark has those teeth, but then I don't know how John Key would look as Prime Minister". First: there are more than two parties you can vote for! Second: if that is your rationale for voting, you should not vote. It is not your duty to inflict the most attractive politician on the world, regardless of intellect, policies or ability. If you can't be bothered doing the very simple homework on different parties, you should not vote.
If you want to vote but you don't know much about different parties' policies, may I suggest this website. If you can't be bothered going through them all, just check out the couple of areas (e.g. education, justice) that are important to you; at least you'll have some idea of what you're voting for.
I also suggest voting for a minor party that supports the major party you want to see in power. Most people vote for the major parties: if you vote for a little one, it'll stop the fat cats taking over Parliament on their own.
Total words today: 1394. (I was still going, but it was midnight.)
Total words overall: 18,061.