Almost anywhere in Toronto you're not further than two blocks from a "closest" coffee shop...
On Yonge and Bloor Streets that is literally true - check it yourself if you don't believe me! If you're not from North America, you may not be entirely familiar with the importance of coffee on the go - it may seem strange at first but you get the hang of it pretty fast. Now when I'm back in Finland, I miss drinking my cafe mocca on the run! So definitely, do try it!
Starbucks and Second Cups are everywhere, and the smaller Canadian equivalent Timothy's World Coffees - try them, they're nice, too. Try the Canadian specialties as well- the Tim Hortons. You may have thought these only exist in the suburbs and country towns... no way! There's a Horton's on Bay Street just below Bloor that is very popular for lunch, plus the police get their coffee and donuts from there all the time - whenver I walked by (that was a lot, I lived two blocks away), there would be a police car, motor bike or a bicycle outside, usually a few at the same time.
You can get a really good cup of coffee from there or the Canadian office regular: the Timbits (the centres of donuts available with all possible toppings). They also offer cheap lunches - not a gourmet experience, but hey, for 4 bucks you should be happy to get your tummy full!