An appropriate minimum for the do it all, legal everywhere, on everything, North American big game rifle, is the .30/06. An intelligent step up from the .30/06 brings us to the 9.3X62 and the big case .375s, which include the H&H, the Ruger, the Styer, the Dakota, the Ultra, both Weatherbys, and a bunch of wildcats and propriety cartridges. An argument could be made for the .416s, which also boast a flat trajectory. A big case .458 is more of a niche cartridge, and although flat shooting, few are willing to shoot them from supported field positions, thus limiting their versatility. If you feel slighted because I ignored your favorite .338 or .35, sorry.