like Lisa said, Canada is a BIG place! Lots to photograph. I can't help you for the whole country, but if you come to Quebec, then Mount-Royal in Montreal is nice. When you're on top of the mountain, you can take beautiful pictures of the city and beyond, across the island. Old Montreal isn't to be missed either, it looks and feels like Europe. You have the same look and feel in Quebec City. The fjords in the Saguenay region are breathtaking, as is the whole Gaspé region, especially the oft photographed Percé. In the Bas St-Laurent region, Le Bic (national park) has great views on the river.
That's all I can think of right now for my little part of the country.