My only three rifles in the "hunting wing" of my safe anymore, all Weatherby Vanguard/Howa Actions...
.25-06
.270 Winchester
.30-06 Springfield
My .270 is my favorite and is a continuation of my "first love"... my first big game rifle was a .270 Ruger 77 red pad tang safety. It would not shoot factory ammo under 2 MOA, but seat a ballistic tip .05 off the lands and it would tighten right up and shoot sub-MOA all day long. It is what got me started with reloading also. I prefer my .270 for all around hunting. If I have to choose one rifle it's the one. I'll take it for back up to either my .30-06 or .25-06 on any trip. Elk to 400, deer and antelope to 500, Moose under 300 (Still looking for that tag draw) it can do it all and I trust it implicitly to hit where I aim every time (Same with the 25, working on the 30...).
Tried and true, easy to find ammo, lots of components and loads, economical, and all have been proven deadly in their areas. My .25-06 I would even be comfortable hunting elk with as it is so accurate, no matter what you feed it. I have yet to find a load it will not shoot sub-MOA.
In the late 90's I had considered going with a .270 Arnold Magnum, but now I realize those magnums, including the WSM, Nosler, and Weatherby, are just expensive fire breathing screaming banshees that are really unnecessary in my opinion.