I've always been a big fan of Western Park. For two years, I worked right opposite it and every lunchtime (so long as it wasn't raining), I would buy some food from Ponsonby Food Court and take it there for a lunchtime picnic. Being surrounded by the lush greenery as well as the beautiful sunken building sculptures is simply hard to beat. The shape of the park is unique and connects Ponsonby to Freemans Bay. Little tip, one of the Sunken Building has a tiny little peeping hole, which if you look in at night you can see this amazing interior of what looks like a church. I'm not sure if this has been fixed, but I was astounded to have found this out many years ago, on a friend's advice.
At the bottom of Western Park lies a great playground. Plenty of different slides means there is heaps of variety for the kids to play on. Our little man is around 22 months old and seems to be pretty fearless on most of them. There is also a flying fox which although he can't go down by himself yet loves to cruise on down with me holding on to him.