My hometown has a market, and this sort of brought me back. Now, my hometown is much smaller than Toronto, but nevertheless the same kind of old market. St. Lawrence is a huge hall, actually two, as there is one across the street that is much newer and much plainer,but still worth a visit.
In the market I counted no fewer than 3 seafood stores, 3 cheese stores (that's not counting stores that had cheese among other things), I'm not sure how many bakeries, and delis. The big market has a downstairs section with some prepared food places as well. Saturdays they open at 5 in the morning, and when I got there at 7 it was going full out. I was able to park on the street using a meter.
Oh yeah, there was also a ton of produce, organic produce, and ever so much more. If you live in Toronto you need to check this place out, if just for the experience. If you're a tourist it is still fun, but you'll want to buy all kinds of yummy things that you may not be equipped to cook in your hotel room!