Preheat oven to 350°. In a large bowl, cream butter and sugars until light and fluffy, 5-7 minutes. Beat in eggs and vanilla. In another bowl, whisk flour, baking powder, baking soda and salt; gradually beat into creamed mixture. Stir in chocolate chips., Drop dough by rounded tablespoonfuls 3 in. apart onto greased baking sheets. Flatten slightly. Bake 10-12 minutes or until light brown. Remove from pans to wire racks to cool.