Why have you narrowed down your choices to only 223, 243, 270 and 30-06? For your purpose and application something in 308 would be ideal. It is light recoiling, ammo is abundant and cheap, it can tackle big game, and you can find almost any model of factory rifle chambered in it. A 7mm-08 would also fit the bill as well with all of the above stated advantages, but ammo is a little harder to come by. Yes, a 243 will be soft shooting and can manage deer but you are limiting yourself to what you can hunt. If you are dead set on a rifle chambered in the cartridges that you have listed then I would say get a 243, then when you have mastered it get another gun chambered in 270 or 30-06. But if it were me i'd be looking at a 308 or 7mm-08