Kira,
Who doesn't love balloons? What a marvelous idea to decorate the church with balloon bouquets instead of expensive flower arrangements. These can be carried to the reception and given away as door prizes too for an interesting and attention-getting idea. Make your wedding original. How many have you attended with balloon bouquets decorating the sanctuary? And how many weddings have door prizes? These are great ideas for a unique and beautiful wedding.
The balloons don't have to be tacky. They can be beautiful works of art in baskets that your guests would love to have. You can find beautiful baskets inexpensively at dollar stores and discount home stores. Go to a party store and have them inflate the types of balloons you want and put the bouquets together.
My suggestion is to practice this several weeks before the wedding and then get fresh balloons the morning of the wedding. Use lots of ribbons and bows in white and your wedding colors.