The Food Lab (website Serious Eats) is a now-famous website that exhaustively tests and experiments with recipes. Their chief consultant chef is J. Kenji López-Alt who is now well into "celebrity chef" status. Rather than copy their Chocolate Chip Cookie recipe, I'm simply going to link to it.
Food Lab's Best Chocolate Chip Cookie
Equally useful is their extensive writeup on how they tested and developed the recipe, which provides helpful insight into how to make the recipe.
The Science of the Best Chocolate Chip Cookies
More info from Food Lab:
Click here for their favorite supermarket dark chocolate bars for baking.
Click here for their favorite supermarket chcolate chips (but note that their chocolate chip cookie recipe actually recommends buying bar chocolate and hand-chopping it).
Click here for their favorite vanilla extracts.