In Celtic Irish tradition, natives engraved the faces of great mythological heroes - such the fierce warrior Cuchulainn or Luga the Sun god - onto the cases of pocket watches, thus inscribing them a permanent place of honor and posterity. On your wedding, commemorate the great heroes by your side, your groomsmen, while endowing them with a little Irish luck with your groomsmen gifts.
Undoubtedly all your groomsmen are heroic to you in some way, accomplishing great feats both during your wedding process and throughout your friendship, and a pocket watch is appropriate and traditional for giving as groomsmen gifts to thank your groomsmen for their important role in your life.
Also, some of your buddies may not have the natural skills that propelled you into nuptial bliss, and might need a little extra help landing a lady. Being as the watch is the traditional sign of secret betrothal in Ireland, (not a bad pickup line by the way) a pocket watch as a lucky talisman may be the token your groomsman needs to get his game off the ground. Adding an old world touch of sophistication and luxury to an otherwise scruffy bachelor, today's pocket watches are still easily engraved, allowing you to tell your friend what a hero he is to you, while upping his elegance ante at the same time.
Consider purchasing your guys groomsmen gifts of a high polish pocket watch, featuring a 1.5-inch face and engravable closure, attached by a masculine removable 12-inch braided chain. Another choice might be a silver pocket watch, popular for its brushed silver color and the stylish wooden box it comes in, adding a certain panache to the presentation. Also comes on a removable chain for the man who prefers a longer leash, but hey, that's why you're getting married and he's not, right?