In a large mixing bowl with a paddle attachment, cream together butter, white sugar and brown sugar on medium/high speed 5 minutes. Beat in eggs one at a time then mix in vanilla extract. In a separate bowl, thoroughly whisk together flour, baking soda and salt then beat it in thirds into the batter. Fold chocolate chips into the cookie dough. Scoop even balls of dough (3 Tbsp each) and arrange on prepared baking sheets. Bake one cookie sheet at a time.