Well how formal are the wedding and reception? Our wedding was quite formal, and our reception fairly informal. My guys were in mid grey suits, with white shirts and grey ties, black shoes. The monochrome look if the suit and tie, plus the white shirt made the lighter grey suit look more formal. I had on mud grey pants and a dove grey vest, so the mid grey, arguably, even made us more formal as a group, in that we were dressed more alike (to a similar form). One of the guys our on a more fun tie for the evenin. One was planning to change into a tux, but lost his pants on the train (was annoying but pretty funny). Anyway I found the mid grey perfectly fine for the day time, plus my wife preferred it. But, if you want more formal, charcoal is more formal. Charcoal is more appropriate to after sunset, though I did not think the lighter suits felt inappropriate at our reception. There are lots of pics earlier in the thread if you want to look. Does anyone else have pics if groomsmen in chArcoal suits for comparison?