There are so many great sketching notebooks in the world, and in my design practice I have tried a lot of them. These Plain Moleskine Cahier Extra Large Notebooks are my current favorite. They don't feel oversized, but they do feel expansive. And, unlike some of the other Moleskine line, these feel like they are working notebooks, neither precious nor showy.
Design Wish — Hand-book Journal Co. 8-1/2-Inch by 12-Inch Quattro Journal, Grid
Good sketching makes good design. And this is a great notebook.