1. The bride and groom.
2. The guests. We're not the kind of people to cut the wedding list in half so everyone coming can get nicer favors. Once we decided we'd only invite family and close friends, that means there is no room or desire to trim.
3. The budget.
4. The decision to get married in a church, especially since our families desire that.
5. Our compulsive desire party late into the night. We met at tango, we're both nightowls, and we both happen to have this vision of an espresso cart rolling in around 1 a.m., fueling a frenzied second wind...
Everything else -- the food, the music, the location, the season, the dress, the flowers, the presence or absence of a gypsy violinist to serenade the guests they imbibe a custom or non-custom cocktail -- is up for discussion. Not to say we don't have preferences (some of them strong), but as long as we consider every other element of the wedding as optional, we'll a) have more bargaining power and b) not make decisions that push us beyond our budget, regardless of that bargaining.
Next: The budget!