In a large saucepan, melt butter over low heat. Stir in the brown sugar, sugar, eggs and peanut butter until smooth. Add oats, baking soda, raisins and chocolate chips (dough will be sticky)., Drop on a greased baking sheet with an ice cream scoop or large spoon. Flatten slightly. Bake at 350° for 15 minutes. Remove cookies to a wire rack to cool.