Personal opinion, it depends on your prefer and how much you want to be cost.
General speaking, you have many choice from Costco, Ikea, The Brick, Best Buy, Future Shop, War-Mart, Loblaws, RONA, and Home Depot. Sears and The Bay are expensive ones. There are numbers furniture stores in Ottawa too.
Watch the weekly special flyers, find better price can save a lot of money.
If you are new owner for a new house, you can contact your builder and may get a *% discount from above shops.