One of the things I love about Auckland is its diverse collection of parks and reserves. Since we moved back from New York (several years ago now!), on weekends we have regularly set out to explore unvisited green spots on the map. We're still finding great new places relatively close to home. This is due to many factors, including having so much coastline (Auckland straddles an isthmus), the many cones, lakes and other features of the Auckland volcanic field, and moderately enlightened urban planning.
Today we discovered the Rotary Walkway of the Wakaraanga Creek reserve at Farm Cove near Pakuranga. It's a paved path in coastal reserves along the Wakaraanga Creek and the Tamaki River. The weather was excellent, and the reserve and the estuary are delightful.
According to the local government's newsletter, the walkway around Orakei Basin has been refurbished, so that will be a good place to visit soon.
A couple of other tips: if you live in Auckland and haven't been to Rangitoto recently (or ever), or you visit Auckland, take the ferry to Rangitoto and make sure you visit the lava caves. It's an amazing place right on our doorstep. If you've done Rangitoto and the other popular Auckland spots, try Mangere Mountain. It's one of Auckland's best-kept secrets.