Coronation Park is a great multi-use park on the waterfront. You'll often see picnicking families, couples on a date, and runners/cyclists stopping for a break before they continue on the trail that runs along the lake shore.
I go there mostly for the fantastic dog park. It is large and fully fenced, with a lovely view and a nice woodchip ground cover. Perhaps because it's a little bit further from the dense residential area, the dog park has not been too busy on the three occasions that I've visited it.
With lots of shade and picnic benches, it is almost perfect. The only thing standing in the way of a 5-star rating is the lack of a water fountain. There's one near the bathrooms, not far from the dog park, but it does not have a dog fountain at the base.