Ontario has been coming out with some really great craft brews. If you have the opportunity look for an LCBO, there selections CAN be really good (can is the operative word, LCBO's around larger cities have a better selection for the most part). Breweries to look for:
Flying Monkey - Cascadian Dark Ale, Hoptical Illusion, Confederation Ale.
Mill St. - Coffee Porter, Tankhouse Ale, Lemon Tea Beer, Organic Lager
St. Ambroise - Oatmeal Stout
Skeena Brewing - Wolfgang's German Style Lager
Trafalgar Ales and Meads - Irish Red, Special Bitter
Great Lakes Brewery - Crazy Canuck, Devils Pale Ale 666, Green Tea Ale, Winter Ale,
Grand River Brewing - Galt Knife Old Style, Russian Gun
LCBO.com has a search function and you can look for brands by store location if you know the surrounding towns. ontariocraftbrewers.com also has a good beer search on their website. Hope I could help, Cheers!