There isn't any Canadian whisky made today, except for a Scots-style malt whisky in Nova Scotia and perhaps any products starting to come from very small artisan makers, that are straight whiskies in the sense (some) American whiskey is straight, i.e., aged a minimum of 2 years in new charred containers and distilled at under 160 proof. Canadian whisky has a different tradition to American whisky. For over 100 years, Canadian whisky is - not by law but by practice - blended which means combining whisky distilled at low proof with a high-proof-distilled neutral-type (albeit aged) base. For a time there was Seagram Pedigree bourbon and rye sold in Canada, in the 40's and early 50's, but that is long gone (and may have been aimed at a bourbon and straight rye market, I am not sure). There were possibly other products, some maybe sold under the name old rye, which were akin to some U.S. straight whiskeys, but these too are long gone.
Lot 40 from Corby was, however, apparently an all-pot still product released some 10-12 years ago and it can still be found here and there in the U.S. It had a strong piny taste and was apparently a flavouring whisky (and still may be) for the Corby Whisky line in Canada. It tasted somewhat like some of the Old Potrero rye whiskies in my opinion. This is not currently available in Canada but it has reappeared here every so often over the last 12 years. I think it would be better with a few years more aging on it and I am not sure if it was aged in new charred wood.
Forty Creek, made in Grimsby, Ontario, off-shoot of a relatively small winery, has a range of whisky products. They are the result of blending whiskies made from rye, corn and barley malt. Some of the components appear to be flavouring whiskies or that type and possibly even are straight whiskeys as the term is understood in the U.S. Certainly the result is flavorful, much more so I find than the Canadian whisky made by the large companies. I advise to try their Barrel Select: fairly widely available in the U.S., not expensive, and good. The new Wiser`s Small Batch is from a large company but has a lot of taste and good texture. It too is somewhat similar to a U.S. straight. And I like Wiser`s Very Old (18 years old) and CR Special Reserve as mentioned earlier too.
So this is the background and I`d suggest looking for the excellent Canadian whiskies I have mentioned because they define the best of it. The straights are a U.S. specialty.
That said, once experience is gained with the Canadian palate, consider adding rye or bourbon to any bottle of Canadian whisky you get to seek a richer palate than any of the producers currently offer. Since 10%-20% or so (more in some cases) of Canadian whisky is composed of a straight-type whisky (sometimes the producers use bourbon or rye made in the U.S. for this purpose), adding more makes complete sense, you are simply improving the quality (if the blending works well of course). A luxury Canadian whisky in the 1950`s-60`s, whose name escapes me, was advertised on the back label as being a combination of bourbon and Canadian whisky. Makes perfect sense, and still does. It`s a continuum you see, you would not be doing anything weird or novel. But like anything else it would have to be approached right. E.g., to add a young bourbon to, say, Wiser`s Very Old wouldn`t make any sense (but it might if you add it to Canadian Mist which is fairly young and uncomplicated). But if you add, say, Pappy 15 or 20, well that`s more what would make it better. You might even go to, say, EC 12, or really any well-flavoured straight whiskey whose maturity would mesh with what you are blending it with. I don`t want to keep harping on do-it-yourself blending. Really. I mention it continually to try to explain better what Canadian whisky is, its virtues and `limits`. It`s all good in other words and more a question of what a specific drinker likes. If he likes and wishes to sample only all-straight whiskey, well, the U.S. has a lot of those and it`s just not something made in Canada. But straight whiskey is still very relevant to Canadian whisky - is part and parcel of its heritage and background. Experimenting with blending can make the relationship clearer IMO.