Without regard to any specific maker, what do you feel is the best standard drilling combination of shotgun bore and caliber? Let's say the intended purpose is exactly what it was originally designed for which is general big game hunting with a mixed bag of small game and upland birds.

There are endless combinations out there and some are fascinating and others cause you to raise a questioning brow. Regardless, I'm curious what others think is the ideal.

I'll start,

My ideal combination would be a 16x16x.270, or a 20x20x.270. Neither is commonly found,