If you have a good 375 Bolt rifle then you need a Double Rifle in 450/400 to 470.

I have no serious big rifle experience but have noted one thing, I can load and shoot .375 H&H cheaper than my favorite 9.3x62mm, 376 Steyr or .458 Win Mag. .338 Win Mag and .35 Whelen are cheaper still, sad to say. Of course if you like something rather than need something, price is no object. Imagine how boring life would be with a .30-06 and a .375 H&H for everything.

You never said if you had a trip to Africa or Alaska planned. If you are going to Africa and are hunting DG, remember that there is a legal minimum imposed for a reason. I have never shot anything that could kill me back, yet, But I do not want to be put in the situation of having to defend myself with the legal minimum. Having said that, I should tell you that I do own a .375H&H, .416 Rigby, and a .500 N.E. DR. I am planning a trip to Africa in 2009 and do not see the .375 making the trip. I have heard reports that the .416 rem. has pressure problems in the heat. If this is true go for the Rigby and load to its original velocity of 400 gr. at 2400 fps. Plus it is a great old nostalgic cartridge. If you ever need justificatio, read Ruark's Use Enough Gun again. Also as another alternative, the .400H&H should be available soon. It will also use .411/400grn. bullet. Good luck with your decicion.