In a medium bowl, combine flour, baking soda, baking powder, and salt. In a mixer bowl, cream butter or margarine, peanut butter, brown sugar, and 1 cup granulated sugar until light and fluffy. Beat in the eggs and vanilla.
Gradually beat in your choice of mix-in's until just combined. If you want just peanut butter cookies, just skip this step.
Drop heaping tablespoons of dough into remaining 1/3 cup granulated sugar. Shape into balls. Place about 3 inches apart onto ungreased cookie sheets. Flatten slightly with a fork dipped in the sugar.
Bake for 10 minutes or until the cookies are just set and are slightly firm to the touch. Do not over-bake. They will crisp up when cooled.
Cool for one minute on cookie sheets. Transfer to wire racks to cool completely.