my vote would also be the .30-06 , it' s got many different loadings , and many different bullet weights for handloaders , and some killer factory ammo such as hornady' s light magnum loadings all the way down to the federal cartridge company' s " accelerator " loads using a .22 caliber bullet inserted into a .30-06 casing with a surrounding plastic spacer ( sorry , at the moment i can' t think what it' s called ) around the bullet so that it will still spin with the bore , and give some accuracy ,

the only other cartridge that comes close in comparison would be the .280 remington