sultanoswing: FWIW you might also want to give Sygic a try. In my limited use so far I prefer it to Navigon... nice map view, more features without having to fork out more $$$ and (I think) more free map updates. It's a bit more clunky to input your address, but it doesn't swing my vote.
I tried Navigon to get from home to work and while it worked fine I didn't really like the colours or all the POIs that littered the map (and I couldn't fine a setting to turn them off).
Am I correct that Sygic costs 29 euros to by the NZ maps?