Depends on a whole bunch of things - where are you hunting, and what for? How comfortable are you with recoil? Do you shoot much? Do you reload?\
If you're looking for something light, not much recoil, but will take any game in Ontario, 7mm/08 comes to mind. If you're going after moose, use a premium bullet. You could also use it for coyotes, it's light, minimal recoil, not too much noise. Pick one up in a Savage or remington and a half decent scope, it would be hard to beat.
Pretty well anything in a 30 cal would be great too. If you're going to concentrate on moose, though, a .338 is awesome, but not everyone can shoot one without flinching. Another thing you could consider is one of the rifled barrel/shotty combo's. Accurate out to 100+ yards, can be used anywhere in Ontario, and you swap barrels out for birds or Spring turkey.