Some lines have rental tuxes available so you dont have to worry about packing one! You will see some people who go all out, and others, like us keep it simple (hubby wears a suit, I wear a nice pants outfit). I pack one pair of dressy pants and two tops that will go with it. I like to be comfy, and given that Im pregnant this trip Im not going out and spending a fortune on a decent maternity dress that I will only wear once!
Its easy really.
Men - Dark Suit or suit separates - dress shirt, tie dress shoes or a TUX.
Ladies - long dress, long skirt with dressy blouse. Dressy cocktail dress or dressy suit.
Dress heels or sandals .
Think of something that you would wear to an evening church wedding with a reception at the local country club or at the best downtown hotel.