Chocolate chip is probably the safest. They are literally impossible to screw up. Underbaked? Then they're extra gooey. Delicious. Burnt to a crisp? Dunk it in some milk, it'll taste like new again. And you can eat like a thousand of them without getting sick because they're rarely too rich to pound a bunch.
A peanut butter cookie with peanuts in it is incredible.
Macadamia and white chocolate, but I can only have a couple before I get sick because they're so damn rich.
If I feel like binging on some cookies, I'll eat an entire box of Girl Scout Thin Mints. Won't even phase me. They're just like chips. No matter how many you eat, you'll never get full, and you'll never get tired of the flavor.