For most big ticket items, such as Nikon or Canon DSLRs, they are more expensive there than in the US (acknowledge you are from Canada) after tax-free is factored in. Be sure to do your window shopping at home first so that you can compare prices. Aside from warranty issue, you might be hit with an import tax at your home country's custom.
In general, I love to browse in the big shops (all mentioned in prior post minus Costco), and do my purchasing back home in the US. My favorite shop is Yodobashi Camera near Umeda Station in Osaka. Den Den Town has lost most of its former appeal since Yodobashi moved. Since you will be in Tokyo, besides Akihabara, Shinjuku Station has a couple of big electronic stores as well. Check the west side as well as the east side of the station.