Since I like to hunt and have been hunting since the age of 8, choseing a rifle would be one that would kill everything I wanted to hunt. Whether that be animal or target. To me that is my custom 300wm, it will take everything from a squirrel to elk.
Actually there is no "one" rifle for everything, it all depends on what you want it to do.
Largest bullet selection of ANY caliber. 55grain accelerators to 230 Bergers, and Everything in between.
Gopher to Griz, near to far. It's the all around king in North America.
My second choice would be the ol tried & true workhorse. The 30-06.
Of course the .22lr, 12ga, 338, & the .375 are also excellent choices depending on the situation.
If I was marooned africa, itd be the .375 or .338.
In Alaska, I'd opt for the 338, or 12ga.
If I was stranded in the northeast, I'd opt for the 12ga, or .22lr.
If it was TEOTWAWKI it'd probably be a 22lr.
But, thank God I was born in the Northwest, & ill die here too, so my caliber of choice is a 300mag.