I have been using this recipe for a while. Its really simple and you can jazz it up any way you like. I personally like milk chocolate chips in mine. I saw a recipe where you can bake them with preserves/jelly and make pb & J cookies.
1Cream the butter for 2 minutes. Add the sugars, cream for 2 more minutes. Mix in the peanut butter and egg. Mix together the dry ingredients-flour, baking soda, baking powder and salt. Stir into the sugar/butter mixture.*Optional* Fold in 8 oz bag of milk chocolate chips
If you want to make it ahead of time and bake later wrap the dough in plastic and refrigerate.
2Preheat oven to 375'F. Shape dough into 1 1/4 inch balls. Place about 3 inches apart on ungreased cookie sheet. Flatten in crisscross pattern with a fork. Bake until light brown, 9-10 minutes. For chewier cookies, bake 300'F for 15 minutes.