Tex:
Good post. You are right on in your assessment of the interrelations of required X and image quality. For shots on big game, for myriad reasons, I prefer the lowest X possible; of course, the better the glass, the lower X you can be comfortable with.
If budget is at all a concern, I haven't come across better values than the SWFA offerings. Their HD series offers way better glass than the price range suggests, and they are known for top quality ruggedness. I can't help but feel that a lot of guys I see at the range with mid to lower tier, high X range scopes would be much better served by the SWFA 3-9, or even thier 6x. Use the money saved on ammo.