There are two basic types of cameras that wedding photographers use, 35mm and medium format. There is some contention, even among professional photographers as to which is best. The 35mm cameras will give you a slightly grainier appearance if the photo is enlarged than the medium format will. Unless you plan on very large enlargements, the only one that will notice this graininess is your photographer. It also lasts longer than color film.
Color is the most versatile of the two.
Color pictures will give you a more accurate portrayal of your wedding day. The choice is usually made according to the couple's tastes. Another consideration is the speed of the film. Most photographer's will already have a standard that they use in certain situations, and the couple won't need to worry about the film speed. 100 speed is best in strong sunlight and is the least grainiest of the three.