There are some nice restaurants in Cabbagetown (the old Victorian neighbourhood) and in the Old Distillery quarter. A particular place is the cider bar Her Father, its the biggest one in North America and the food is quite good as well.
It all depends on what you like but must sees, Kensington market, distillery district, the ROM, china town, blue jays or TFC games are a lot fun in the summer, CN Tower is a tourist hot spot, Niagara Falls is a day trip away, st lawerance market (get a Canadian bacon sandwich), Queen st west, and… More
Nu bugel for Montreal bagels. Crepes a go go is also yummy. Sweet baby Jesus for ice cream. For activities I would recommend free tours by foot. You can get a feel for the city, please bring cash to tip. These guides are awesome. Definitely the distillery district.