For hunting it is hard to beat either the .308 or the .30-06 depending on which action you prefer. The great success of the .308 is due mostly to its caliber, low recoil, its military applications, and relatively cheap brass. The .308 advantage over the .30-06 is the use of short actions and improved cycling in fully automatic weapons.
The only drawback of the .308 is its velocity with high BC bullets. Even the .30-06 does not cut it for very long distances. For such a task, you need the .300 WM or the almighty .300 RUM. Both of these calibers kick like mules w/out a brake and the .300 RUM is also n an expensive brass to acquire, even as a reloader stand-point.
For target shooting, there are better options for the .308 case, namely the .260 R, the .243 W, and to some extent the 7-08. The .30-06 case is impressive as the .280 R, or better yet AI.
Again, for hunting it's hard to beat either the .308 or .30-08. For long-distance target shooting and sniping, there are better options but at times at the expenses of high recoil unless one downsizes the bullet.
There are reasons why there are so many calibers out there, just figure out what your needs are!