Be forewarned, however, margarines differ widely and so do their melting points and flavors, and the textures of the cookies made from them. They'll dramatically change the texture of your cookies. You'll want to use a real vanilla extract rather than an imitation vanilla flavoring since this is one of the four critical flavors contributing to the perfect cookie. If you're obsessive-compulsive, you may want to use a great vanilla extract. We like Nielsen Massey, but use what you prefer.
Sugar sweetens a cookie, but it also tenderizes and competes for the water.
Too much sugar will win the battle for water and cause the cookie to spread more than you probably want it to. Too much sugar also will make the cookie brittle. The conventional recipe for chocolate chip cookies requires half granulated and half brown sugar. The cook can change the proportions, but the cookie will change too. Use all granulated sugar and you can expect a lighter-colored cookie.