I attended the recent StatsNZ roadshow on Census info this week, along with Patricia Jordan, and of all the powerpoints and information presented one of the key resources that struck me as potentially useful across a range of disciplines was the Quarterly Regional Reviews (now freely available on the web).
These QRRs include stats from a range of agencies, so there are Hospital and Crime stats as well as car regos and the standard Stats NZ data as well. All bundled in a single PDF file.

For the full SNZ PR blurb about what’s being made freely available that wasn’t before try the MIFA page. INFOS, for example, is intended to become a web based product some time in 2008.