well one I can be certain of, and that is a 260 Remington. You could give me a 6.5x55 instead and I'd be just about as happy, but the 260 is the one for me in the short action rifles. Anything from long range predator hunting, ideal for deer inside 1/4 mile, and can handle moose/elk in a pinch with good ammo and good shooting.
If I had to pick two others that I have actual hunting experience with that I like, would be the 243 Winchester for long range coyote hunting, and the 7mm Rem Mag for deer, moose, and black bear. Ive had great results with those two cartridges