Not having had any experience with any of the great English single shots, but having admired them from afar, I would have to bow to other's opinions therein.
As for American mass produced stuff suitable for an astonishing range of cartridges I have to nominate the Winchester High Wall, vintage or modern MVA. (An MVA action is headed in my direction as we speak, to be mated to a Ron Long .32-40 barrel.) For shear American elegance I love the Marlin Ballard, but they're becoming difficult for an old fart on a fixed income to own!
All that said, my go-to hunting rifles have been Ruger #1's.
