Almost every post when people ask about calibers they are recomended the .223 because its cheap and available and gets the job done. It has nothing to do with it being the best caliber.
Personaly I like the idea of fancy calibers but don't reload YET so for now they make no sense. I think most guys are in the same boat. 10mm is the only oddball that I have so far.
With so many choices out there I don't think any caliber is really the best. You have to consider ammo price, reloading, trajectory, bullet availability and their design, how much powder it burns, barrel life, recoil, muzzle blast, killing power, the rifles chambered for that caliber, hunting regulations,accuracy and so on.
The .223 really is the ultimate trade off in a varmint/predator gun. Middle of the road performance is the trade off for cheap and widely available ammo. Also a long barrel life is nice.
I would like a .204 for shooting smaller critters. Like jack rabbits and prarie dogs.
.221 FB, 22hornet,or .222rem for calling dogs in the woods.
.223 just because its so available.
.243 for lions,occasional big game, open country, the ultimate jack of all trades master of none.
I have no use for a larger caliber.
Variety is the spice of life!