Between the various cartridges available with a .277" bore, I would choose the .270 Winchester as well. Choose your rifle carefully, letting neither cost alone, nor the flavor of the moment distract you from making a wise purchase. Consider the quality of the rifle, the materials it is made from, and the features, and physical dimensions you want. It is not up to me to tell you one action is better than another, or that wood is better than synthetic, but the action should cycle smoothly and reliably without undue effort while at the shoulder.
Good wood for stock material is becoming increasingly difficult to find in a factory rifle, and uber expensive in a custom. In synthetics, stay away from cheap tupperware stocks, fiberglass is what you are after. A good fiberglass stock is far from cheap, but it is far cheaper than a piece of presentation grade wood. The fit of the rifle to the shooter is more important than many realize, but you might find a factory stock almost perfect, or you might have to try many types to find the right one. Don't rush into the first thing that catches your eye, take your time, look at as many options as you can, and enjoy the experience.
The trigger, is perhaps the most important and most often ignored component of a rifle. The break should be clean with no perceptible movement, neither creep nor over-travel. The reality of trying a number of off-the-shelf rifles may cause you to think that this is all but unobtainable, but some factory triggers come very close to the ideal. The weight applied to the trigger to cause the rifle to fire most agree should be between 3 and 4 pounds on a big game rifle. Should you choose a semi-auto, the trigger probably won't be as good as found on other actions due to the number of things that the trigger must accomplish; releasing the sear then catching it again. There is no need for the semi-auto's trigger to be horrible though, yet some are, while others are surprisingly good. If being able to adjust the trigger matters to you, I think you are pretty much stuck with a bolt gun, but not even all bolt guns have fully adjustable triggers.
I prefer to have iron sights on a big game rifle, and I enjoy shooting with irons. You may not, but you should consider the redundancy factor particularly if you hunt in true wilderness. While an open rear sight simplifies the mounting of the scope, the ghost ring and post provides the best precision, and some models are designed to flip down into the rear scope base.
Choose the scope with care as well. Leupold is the only make with a Canadian warranty center, and their turn around has always been very quick when I've had reticles changed, or new for me used scopes checked out. The advantage of the scope is that magnification is not the prime advantage, the advantage is that both the target and aiming point are in simultaneous focus. Don't get caught up into thinking that the more magnification you have the better your scope is. A variable power scope might make you rifle more versatile, but in truth a 2.5-8X is all you'll need over normal hunting ranges, even if you intend to use the rifle for coyotes now and then. Scope mounts should be strong, so avoid the cheap junk. The height of the scope above the bore is best when mounted as close to the barrel as possible, but you must be able to see through the scope when you have a good cheek weld on the stock.
Lastly, I like to have a shooting sling on my rifle, rather than a simple carry strap. The best of these IMHO is the Galco Safari Ching Sling, which allows very fast sling up time, with no more bulk than a cobra strap. If slinging up doesn't interest you, consider that your chance of hitting from supported positions increases about 30% if you can sling up.
