I know this topic has already been much discussed, the report has been written, but still I couldn't resist adding my own 2 or 3 cents.
One trick that I noticed was implicit in some of the recipes, but bears mentioning as it can (and should!) be applied wherever you want to achieve that perfect crisp/cewy texture in your cookies is to chill the dough at least overnight. 24 hours is even better. Make that 48 for oatmeal. It's not the temperature that makes the difference, it's the time. It gives teh flour more time to bond with the liquids, or something, I don't know. All I know is it works!
There's also another book which is a must have for every cookie lover: Big, Soft, Chewy Cookies, by Jill van Cleave. Every recipe I've ever tried from it has been fantastic, and I've tried many.
Finally, I also noticed you're missing the recipe for the world's best peanut butter cookies...
1 cup peanut butter (crunchy or smooth, your choice)
1 cup sugar
1 t. baking soda
(I've also been known to throw in a handful of chopped chocolate from time to time)
No, it's not a type-o. These cookies contain no flour, and no butter.
Preheat oven to 350°F.
Stir all ingredients together until well combined.
Roll teaspoons of dough into balls and arrange about 1 inch apart on ungreased baking sheets. If dough is too soft to roll, let it sit 10 minutes and it will thicken.
Flatten balls with the tines of a fork.
Bake until puffed and pale golden, about 10 minutes.
DO NOT OVERBAKE THEM or they will be dry and crumbly. These cookies should lovely and chewy.
Happy cookie baking to everyone. Mmmm, I love cookies.