Preheat oven to 375ºF. In medium bowl, combine flour, baking soda, and salt; set aside. In large bowl, with electric mixer, beat margarine and sugars until light and fluffy, about 4 minutes. Beat in egg and vanilla until blended. Gradually beat in flour mixture just until blended. Stir in chocolate. On ungreased baking sheets, drop dough by rounded teaspoonfuls, 2-inches apart. Bake 10 minutes or until edges are golden. On wire rack, cool 2 minutes; remove from sheets and cool completely.
Per Serving (Using Splenda):