http://webpages.charter.net/375magnum/allrd.htm

"The actual necessity for a .375 H&H - or any cartridge of similar or greater power - is quite limited in North America. Brown bear, polar bear, the largest of the interior grizzlies, just perhaps bison, and you've said it all. However, unlike the shorter-ranged and much harder-kicking .416s and larger calibers, the .375 H&H is both shootable and versitale."-- Craig Boddington, American Hunting Rifles, Safari Press (1995), p. 142.

For Alaskan Brown Bears, the "[b]est of all, to my mind, remains the 1912-vintage .375 H&H. It has the reach if you need it - but, and this is more important, it has the knockdown power for close-range work."-- Craig Boddington, American Hunting Rifles, Safari Press (1995), p. 366.

"The beauty of the .375 H&H is simple: you can take every animal on earth with the caliber without ever being over- and only rarely undergunned." -- Peter Hathaway Capstick, Safari: The Last Adventure, St. Martin's Press (1984), p. 97.

I would have to choose my Sako A7 in 300WSM.

I think the .375 is a bit much for North America and is on the small side for Africa. A.416 Rigby or the .338 Lapua which is based off the .416 Rigby would be ideal for Africa

Nothing currently inhabiting this planet that a .375 H&H won't knock it's stick in the dirt!

Since the focus is on North American hunting I would delete the 375. Owning this caliber as an all around for the off chance to Hunt big bear might make for a lot of uncomfortable deer hunting around home. Stick with an 06, any of the 300 Mags, or 7mm Mags and you will be a happy camper, even if you hunt an Alaskan brown bear on that once in a life time hunt. I have been lucky to hunt all over creation with many, many calibers, and there is no" one size fits all". If most of your hunting is for one or two species stick with what you like best for them. For example, here is my bear history. One Alaskan Brown Bear with a 375, another with a 338. Two grizzly with a 300 Win Mag. Polar Bear, a 338. Black bear one an 06 one a 7mm Remington Mag. The only one that took more than five steps was the Alaskan Brown shot with the 375. Do not get me wrong I love the 375 have killed tons of game in Africa, a couple of elk and the one bear with this terrific caliber.

ken.mcloud said it best!

“So, I think that the superior killing power of larger rounds is largely in our heads.(likely testosterone induced) A flat-shooting round that you can accurately place will produce as many if not more "bang-flop" kills as a heavy caliber round.”
-
On the other hand
-
"We have not heard from Ken McCloud in ages hope he was not carrying a fast stepping small caliber rifle and ran into a testosterone laden elephant that could not spell hydrostatic shock. Just teasing Clay.

Kindest Regards"
-Happy Myles

I would have to agree that the 30-06 is a pretty good "one-size-fits-all". It will take anything on the N.A. continent as long as the range is not too far. The .300 mags give us more range and power for bigger bullets but if you are shooting something real big, the range will be less anyway.

I love the .375 but am cautious about where I use it for deer and coyote hunting. The bullets penetrate trees and keep going. In a highly inhabited residential timber, they might penetrate a couple of houses after going through your whitetail.

I guess that is why I never liked Russian dress making... that "one-size-fits-all" mentality just leaves too many things hanging out on the fringe.

I love seeing Happy weigh in with practical real life experience up the wazzoo! I also love having more than one rifle so I can really enjoy hunting across the wide spectrum of North American game and target shooting to boot.

Much farther than most of us should shoot. I have taken just one critter with my 300 Win so far, a 3 point buck at 322 yards. I think that I could take elk, moose out to that range without a hitch, but I personally don't shoot beyond 400 yards at game unless its a coyote, or some other varmint. I'm not against long range shooting, its just my preference to try to keep the "hunt" in hunting as much as possible.
As a side note, the old 300 Winchester is one hell of a rifle too. I have shot it alot since I bought it 2 years ago and I love it. I'll never have to worry about having enough gun for anything I'll ever hunt. I think that the newer 300WSM fits into that same category as well.

.300 weatherby. has a bit more juice then the .300 win mag and can be used on a brown bear hunt. its overkill for smaller big game like whitetail, but mule deer and up its an optimal choice.

i would have to say 300 win as well

My great uncle took moose, grizzly, sheep and caribou in the Yukon and Alaska a hundred years ago. He had three rifles. Two 94 Winchesters, one in 30-30 and one in 25-35. The other was a model 92 in 32-20. He used the 32-20 more as a trail gun. Alaska of 100 years ago when two legged predators roamed the goldfield trails. The point is that we generally have way more gun than we need. The 30-06 is plenty of gun but if you are spending $10,00 for a guided brown bear hunt why not jump up to a .338 Win mag or a .375 H&H/RCM class rifle if you can shoot it well. Why limit yourself to just one rifle caliber?

You know, it's been said many times... but it rings true - Shoot whatever you feel comfortable shooting and can shoot well. With this being said, I would keep the caliber to a minimum of a 7mm/08 or .308 with good ammo. Personally, I shoot a .270 because I shoot it well and the Hornaday SST ammo that I use is very effective on everything from whitetail to moose and black bear.