A Favourite of mine is Mad Tom IPA by Muskoka Brewery. Creemore Springs also makes a very nice Lager. Flying Monkeys Brewery has some cool beers too, namely their Hoptical Illusion and Smashbomb Atomic IPA. I would highly recommend Mill Street Brewery's seasonal sampler pack. Their beer is excellent an their Tankhouse Ale is awesome. Amsterdam Brewery's Boneshaker IPA is great.
By the way, you won't be able to find some of these beers at the beer store. You should check out an LCBO, it's our liquor store that generally has a wider selection. Just make sure you go to a larger one for better variety.