To add to the above, presicion is what most shooters will be going for. The test of a shooter is the shot group. If they can shoot consistant groups, no matter where on the paper the groups are, then they have a good rifle and shooter.
If you are a precise shooter, the rest is up to the scope. If you shoot tight groups, like moxgrove said, all you need is scope adjustments.
There are sometimes where my scopes have been a little bit off, and even in a few shooting session, I didn't take any time to fix the inch or so it was off center; but when it came down to hunting season, then I make sure the scope is dead nuts center. Then I know its all up to me.