Definitely, the .404 Jeffrey.

As Gregor Woods noted in his book, Rifles for Africa, the .404 cartridge in a magazine rifle was used nearly universally by the various African game-control departments. It combined effective "stopping power" with the least amount of recoil of the typically available .40-bores. Thus, for those using it in a tight situation the .404 Jeff offered controllability. For those reasons it's still a great big-game cartridge today, as well as being an "African Classic" in the traditional sense.

Too bad another fav of mine didn't make the list of "neglected" African cartridges: the ol' 300 H&H. It's also a grand old classic.