I've had both.30-06 and .308's. Both fine cartridges. I would agree that the '06 is more versatile for hunting, and the .308 more accurate for target. However, the way target shooting has gone recently with custom guns and calibers, the .308 is outmatched at the top levels. Even service rifle is using heavy bullet 5.56 in tweaked ARs. If I only had one, I'd go with the .30-06. Just my opinion, and worth everything I charged you for it.
Its easier to make a larger round behave like a smaller one that it is to maker a smaller round act like a large one.
"If I only had one, I'd go with the .30-06."
I absolutely agree with this statement, but who can have just one?