30-06 over .300 win mag?
For my purposes? Keeping in mind that my personal choice of cartridges/chamberings has no bearing on what you will need in the Yukon, though I believe it would be acceptable for the areas of the province I have been to.
When I worked at a gun counter I was always suggesting the 30-06 because of its versatility and the way many rifles (like the tikka iirc) are standard length actions for most calibers anyways.
I have a .338 if I for some reason feel the need to open up a medium bore can of whoopass.
If I was buying a tikka ultralite, it would be in 30-06 because the recoil in even the "lite" model in the magnum calibers is wild and crazy.
Here comes the unpopular part: I am not a fan of the 300 win mag. I am not a long range shooter or hunter by any stretch of the imagination. I like big bullets, moving fast or slow. The .300 win mag has a hell of a following in my new home of Alberta though. Most I have encountered praise its long range potential over the 30-06, for me both are fully capable of medium game within and probably well beyond any range I would shoot an animal.
In my mind the 30-06 does everything the 300 wm does for less money and less suffering, brass at every range (applies to the .308 even more I guess) and ammo in every store (again, .308 and 300 win mag). I guess if I am going to get walloped in the shoulder it might as well be for medium bore cartridge instead of a .30 cal.
So basically tl/dr personal preference.