Unless you’re only in town for 48 hours, hiring a car is a great idea. There’s just so much to do within a couple of hours of the city that you couldn’t otherwise experience. Niagara Falls is just a 90-minute drive and a seemingly endless number of quaint lakeside towns and villages, coves, wineries and national parks are scattered along the shores of Lake Huron, Lake Ontario and Lake Erie - within a couple of hours drive of the city. If you’re in Toronto for three days or more, make sure to see what lies in the city’s backyard. If heading east, check maps for “old roads” such as Old Kingston Road to the east of the city — it makes a much nicer drive than the newer chock-a-block expressway equivalents alongside.
Keep in mind that main roads can get pretty hairy between 4:30pm and 6:30pm.