One of the places I knew I really wanted to visit in New Zealand was the Coromandel Peninsula, I kept seeing pictures of Cathedral Cove and felt we needed to go there. I wish we had had more time, it was so beautiful. In a way it was lucky, because the first morning there it was grey and drizzly and so we had to just stop and rest, look at the view and relax and eat crepes (or grapes as Elroy says) for breakfast, but then by the afternoon it had burnt off into the most stunning afternoon.
I don't think there was anywhere we went in New Zealand that we felt disappointed by, everywhere we went the scenery was amazing, the people so friendly and it was easy. Which is exactly what you want when traveling with a three year old. We will definitely be going back sometime.