Lake Pukaki doesn't have a bad angle, which means there are plenty of places to stop and take in the view! Lake Pukaki Viewpoint is one of the most popular places to view the lake and has facilities like picnic tables and toilets.
However, because it's so popular, it's usually packed with other travellers. I recommend driving a little around to the righthand side as you approach the viewpoint. There aren't any facilities, but it's so much more peaceful. We sat here, admired the view, and felt like we had the whole lake to ourselves!