RE: What rifle will cover ALL my needs???
I'd recommend the .30-06, as far as deer are concerned, the only difference you'll EVER notice in performance between the .30-06 and the .300WSM is recoil, the WSM is going to kick quite a bit more, but it won't give you any more practical performance, i.e. it's still only a 600yrd maximum deer rifle (in the best of shooters' hands). For elk, the .300WSM would get a SLIGHT advantage in the form of better performance with heavier bullets, as I mentioned, only a very slight advantage...since you'll only RARELY hunt elk with it, it's not worth planning that into your purchase, the .30-06 will do quite well-you'll never notice the difference only hunting them once or twice-the recoil isn't worth the once or twice use and barely improved performance IMHO.
Also, last I checked, the WSM cartridges were about 1.5-2x the price of .30-06 cartridges in the same loading, I don't know if this is still the case, but it's definately something to consider.