Are we strong today? Strong enough? With the US by us, of course. But without its intervention on our behalf we could easily be taken.
Relatively speaking, Canada is a powerful country. Its economy is very impressive, even when placed alongside most other developed nations.
Would it be that way without the US? Depends... We'd basically have to do the impossible and imagine alternative histories where it isn't affected by the USA as it is in this reality. This really is impossible to do, when we can't even make sense of this world that we actually live in.
Yes, an overwhelming amount of the trade and innovation, among other things present in our country today, is due to our neighbours below... In reality, much of our prestige can be attributed to them. Let's just try and use our imaginations for a second though and picture some other possibilities...
So in alternative world number one, if we were somewhere in South America, chances are good the nation would be little compared to how it is now. I can hardly go into better details than that, but it would make an interesting project for this forum to discuss just that. This merits more thought than the one sentence I give it, but I will continue on to the next alternative just to make my point.
World number two. What if the US didn't exist on the continent of North America? What if there was only what would become Canada?
Then what would you say about not having the United States around? We'd probably be insanely powerful as a nation. We would have an entire continent to ourselves, surrounded by two oceans, away from all of our enemies (except maybe Mexico, heh), with an even greater abundance of natural resources (much like the US enjoys today, along with us).
Of course, then again, we might still be a part of great Britain, but then again, potentially we might not be.
Same could also be said if the United States had all of Canada right from the start of things. It'd have all that much more.
This could make for an interesting discussion... but if there is a point to be made, it is that this sort of discussion is ultimately pointless. Still, it'd be fun, and that might be worthwhile, just as it seems to be worthwhile for some to discuss the potential of conquering Canada, and worthwhile for some to scoff at Canada's position because they think the only reason it was made powerful was from being neighbours with the US. When in fact, there are other reasons (geographical reasons, for example).
(Ceteris parabis applies as much as possible in my simply alternative worlds, of course)