Originally Posted by unbelragazzo
Medium grey would make the groom less formal than the groomsmen, and also doesn't look as good next to the white wedding dress IMHO
Yeah, it might be a bit less formal, but who cares? That's a subtlety that will be completely lost in a venue where men typically dress in what are charitably described as clown outfits. Aesthetically, it would be a nice way to array a wedding party, and if the groom's suit is much nicer and fits much better than the cheap black suits the rest of the guys will be wearing, then he'll come across as being on a higher level anyway.
As for a gray suit looking bad next to a wedding dress, utter bunk:
Excuse the cut and hemming of the trousers- I just pulled this off google.