I love to contour my face - I am not at all blessed in the cheekbone department, and as such I contour every day. My tool of choice depends on the intensity needed and the effect desired: I use a small setting brush for a precise, heavy contour, a loose blush brush for a more everyday contour, and a normal firmness blush brush for those in between days.
This little beauty is my Crown Brushes Fan Brush, and I generally forget about it. In the past I only ever used it for highlighting, but randomly used it with my Kevyn Aucoin Sculpting Powder the other day, and loved the effect. It gives a defined, yet very natural contour, but can also be used for warming up the face using a normal bronzer. I love this brush - the fan shape is perfect for hugging the facial contours.