Recoil=300winmag is a step up from the '06. 338 is a definite step up from the 300. 300weatherby is even stouter then 300win, and in the ballpark of 338. 300wsm would be a little less than 300winmag, and with some patience could work for a newbie. 7mm rem mag is a tad sharper in recoil then the '06 but good for all NA game, though not as good on the really big stuff
Price of ammunition=300winmag, 300wsm, 7mm mag will all be close in price, and availability. 30'06 will be a tad cheaper, and anyone who sells ammo has it. 338winmag will be higher, and anything weatherby willl be higher yet.
killing power (I want an all north america games gun including bisons)=338winmag wins the kill factor here. The 300 mags are all pretty close in killing power.
Distance=This is more related to your shooting ability then the gun's limit
Accuracy= With newer guns, this is more dictated by you, and flinching than the gun. All will shoot good.
And versatility in terms of games (lets says from sheep to bison)
What caliber would you choose?= All will work on all the game, though the 338 is better on big stuff, the 300s are pretty well rounded.
Since I am knew to this, recoil is my biggest concern as it might be unpleasant and affect my accuracy right