The .375 H&H is a total classic!
As noted above, doing so much for so long - not much more needed than a good 375 for big game.
I must say, unfortunately, I don't have a .375H&H right now. This is one of the few bolt guns I really need. Having said that, I'm not sure it really does anything better than my .360No.2. Lighter, faster bullet in the 375 I suppose.
IMO, the .416 Rigby would be my choice if I could have only one rifle for big game - dangerous or not.