I agree that big, heavy guns, LOOK more aesthetically pleasing with larger scopes. Just as smaller guns look more "correct" with smaller scopes.
Functionally, I very much agree with VT, your scope is your direct interface with the target, and should be tailored to fit what your needs may dictate.
A general use rifle will, usually have a more adaptable optic by necessity. Specific task guns will often have much more specialized optics, and while they CAN work in other settings, they are not as easy to use.
I have know a guy with an expensive, fixed low power scope, with a very large objective on a 700 Sendero .308. He uses it for shooting pigs out of the packing shack on his papaya farm. Its a VERY odd combination of rifle, scope, and usage that works perfectly for him.
One of the neat trends in optics is the wide power band scopes, Ive got a few lower cost scopes with 5x power bands, making them much easier to use in across the board conditions.
This give you the option, should you want it, of having a lower min power on a big gun with a big scope, or a higher max power on a little gun with a smaller (they still arnt little) scope.
Im not sure if they are any more susceptible to zero drift as the power changes, than shorter power range scopes. I havent noticed it, but i usually shoot at 3,6 and max power just out of habit.