I'll throw my two worthless cents in the hat.
I have the 243 and the 25-06 snd the 270. I have killed deer with all of them, Mule deer, Black Tailed deer and White Tail deer. My kills have been from 30 yards to over 400 yards. I've used them all on coyotes to gophers, prairie dogs etc.
I would take the 243 or the 25-06 long before I would go 270. The 243 shoots soooo smoothly, the 25-06 anchors deer and coyotes like a hammer. The 270 is often times just a little too much caliber and makes huge holes in everything that 130 grain bullet passes thru.
The 25-06 is a great caliber and I believe is most notably the best sutied caliber between the three "IF" you are going to use it for deer too. Otherwise for coyotes and occassional deer hunting, the 243 would be my first choice. I laugh at guys that take 300 mags or 338's deer hunting and they tell me a 243 isn't capable of cleanly killing deer????
This deer taken with a 243 100 grain SP about 60-75 yards. One shot, one kill.
This deer taken with 243 100 gr SP at 189 yards three shots but one hit in the leg two in the neck.
This deer taken with 243 95gr Nosler Ballistic Tip at over 300 yards, one hit, one kill three misses, he was running hard away /ubbthreads/images/graemlins/confused1.gif
Three other deer were taken with a 243 in my presence and all dropped like a sack of spuds. The 243 is a great choice as is the 25.