I have own a couple of 300 wby. Its the only choice in your line up for me. I would get a 6.5 cm, 260 rem etc for the smaller stuff and good barrel life.
Just sold a 300 WBY for a 300 win mag. only reason being is for price per shot and large amount of factory ammo that can be had just about anywhere. I also went with a leupold mark 5 HD scope. I did a lot of research and seems to me like the best bang for your buck. I like that it has a capped windage turret too that you can obviously leave off if you want for target shooting.
300 for sure. . You'll be able to push heavy high bc bullets at very good velocities. Sure it might be a touch overkill for hunting deer, a 6.5 would work great in that application. For elk size game or especially moose you'll be glad you have a 30.
If you don't reload I would be looking at a 300 win mag*
For a scope, I just bought the new Vortex Razor HD LHT 3-15x42. I believe it's the best hunting scope Vortex has made yet. Upgraded from one Razor to the next.