Normal lodge dress code is a dark suit and black tie (or the relevant masonic tie). Some lodges like mine are Dinner Jackets (Tuxedo). Provincial and Grand Officers wear a 3 piece morning suit (striped trousers with a black waistcoat and jacket).
My lodge is meeting tonight so I'm sat at work with my DJ trousers and a white shirt on and my DJ jacket in a suit carrier.
I agree that the man is more important than the exterior, but the way we view things over here is that it's not much to afford a black suit nowadays, and it means everyone looks more or less 'uniform' and therefore on the level. Culturally we tend be rather formal over here anyway.
We once held a meeting on the same night as a carol service in our local cathedral, so we were told that we were just going to open and close the lodge and open the festive board more like a ladies evening and DJ wasn't necessary due to the service, just wear a lounge suit. I wore a black suit as per normal, but with an orange tie and that caused quite a stir!