The Downsview Market food court is amazing. "Food Court" doesn't really do it justice, but I don't know what else to call it.
There are so many different kinds of food, it's really affordable, and the owners are friendly and open to suggesting dishes for you to try. Sometimes DH and I will go just for a smoothie from one of the booths, where they sweeten it with fresh sugar cane that they press/crush right there. (If you happen to go, I recommend the soursop/pineapple combo!)
For burgers, it's a toss-up between Yellow Griffin in Bloor West Village (website)
and Burger Priest (website)
And my favourite ice cream/dessert place is Dutch Dreams, at Bathurst/St.Clair (website)
And if you're in/near London ON, the best cupcakes EVER are at Ra.zzle Dazz.le Cupcakes (website)