Wow! Some great answers and advice there! I have to admit to playing devil's advocate a little. I figured more of you purists out there would've gone apoplectic with the mention of a push feed Remington 700 being used for a custom DG rifle build!
Looking at the poll results, I honestly thought the .458 Lott would've gotten a little more "love" than it has.
I considered adding the .416 Rem Mag to the list and a couple of the NE cartridges, but didn't simply because they are not currently factory offerings in the CZ 550 rifle that I'm probably going to end up with...someday!
From a purely practical perspective, the .375 H&H is obviously the most versatile choice there, and certainly makes the most sense for hunting N. American game.
However, there is a certain appeal and mystique associated with the names Rigby & Lott, especially if you're ever going to make that African safari a reality. I've always liked both the .416 Rigby and the .458 Lott. I'm not recoil sensitive and can shoot the .458 Win Mag well. The Lott isn't that much a step-up, but offers just a shade more performance, plus the ability to shoot factory .458 Win Mag ammo in the same package.
The .416 calibers have always seemed like a sensible compromise between the minimum legal African caliber, the .375 H&H and the big, big boomers. I don't expect I'll ever have the cash to drop on an elephant, rhino or hippo hunt, but Cape Buffalo and maybe Leopard/Lion are doable without the 6/49 entering into the equation sometime in the future!
I had the opportunity to shoot the .416 Rigby and have to say I loved it! Certainly not as punishing or nasty as I had been led to believe. Besides, who wouldn't have a smile on their face shooting anything with the name "Rigby" attached?
Cost of ammo is indeed crazy, but as I reload and even cast my own bullets, that issue is somewhat mitigated. None of these rifles, however, with maybe the exception of the .375 H&H, are rifles that you're going to shoot 2-3 boxes per range visit anyway...I don't care how recoil insensitive you are!
I think, probably my top three picks would be the .375 H&H, .416 Rigby and .458 Lott. In pure practicality, the .375 H&H wins hands down, especially for longer shots at Moose/Bear in North American and on smaller plains game in Africa...but then again, we're not too wrapped up in a purely pragmatic decision-making process, as were talking about taking "our" new rifle to Africa after dugga boys and elephant!

That keeps the other cartridges still in the running!
The one cartridge I'm a little hesitant about, however, is the .505 Gibbs...that is one beast of a cartridge!
