No place in the Berkshires is dressy in ski season, that's the good news. I second the Castle Street suggestion (downtown Great Barrington, where the food is good, though, as Scott said, there's no fireplace. 20 Railroad Street (also downtown) also work, as will Barrington Brewery, which is a little farther outside of town (also as Scott said). The Pub at the Red Lion Inn would work for all categories, except it's not in Great Barrington (though it's not terribly far away).
Because I love good food, Castle Street would be my choice, but I don't drink beer, so a brewery never much appeals.
Or-- if you call my parents, I'm sure my 83 year old dad would ski with you while my mother would love to cook a mean coq au vin (and they have a fireplace)!