Although an ardent .45ACP fan, my choice for a 1 only cartridge had to go to the .357MAG.
Great PD round, also good enough for up to deer sized game at a respectable distance (although I think that is pushing it), a lot of solid platforms to launch the round, carbine rifles are available chambered for it, easy enough to control - I could probably go on.
It the .41MAG were available in as many loadings & platforms, I would have chosen it instead.