I love the idea of making your own wedding dress and resisting the rule which says your dress has to be ridiculously expensive. I once saw an idea in which the bride-to-be embroidered scenes that were important to her and her fiance at the bottom of her wedding dress. By putting your own touch on the dress, you give the wedding a less stiffly formal feel and a bit more personality. The wedding is about you and your sig other after all!
If your sewing skills are not the best, you can go half-way. Buy a plainer white dress and embellish with fancy accents, like this project for a Die-Cut Wedding Dress.
For more ideas, check out Homemade Wedding: The Dress.