If you like parks, you gotta visit Eglinton Park. I have been frequenting this park for nearly 5 years and still love it. It's a great shortcut from Roselawn to Eglinton on the path by the jungle gym, and the hills make for fun fetch sessions with your pooch.
Unfortunately, there is no off-leash dog area here but there is ample space. Towards the gardens by the public pool is usually less busy than where the playground is. Some days, the park is filled with tons of kids and parents--making it difficult to play fetch; and some days the park is filled with lots of dogs. Also, on the nights there is hockey at the community centre you will NOT find parking. I know it's on Mondays during the summer.
But, it's nice to bring your dog. I would give it 5 stars if the water fountains work. Dogs (and people) get thirsty too!