I live in Toronto. It kinda feels incestuous to think of my own hometown in terms of tourist attractions, though. Like trying to recommend a cousin to a friend.
My personal "favourite places to be" are the libraries, especially these two: the
Toronto Reference Library and the
Merril Collection of Science Fiction, Speculation, and Fantasy.
People don't usually direct tourists to libraries, but it is actually the first thing that came to my mind. They are like home to me.
In addition to libraries, Toronto is host to a number of galleries and museums, most notably the
Royal Ontario Museum and the
Art Gallery of Ontario.
I went to
Ripley's Aquarium of Canada not long ago, and that was pretty interesting.
Toronto also has all sorts of events and festivals. Whenever you are coming there is always something going on. I prefer to avoid those, but I am introverted so what do I know?
Toronto has a tourism website, which has information, probably.
There are loads of good restaurants to eat in, and parks or communities to walk through.
Feel free to ask about anything.