My favorite piece of gear is the 70-200mm lens. It covers such a wide spread of focal lengths and can be used for a variety of situations. The lens stabilization built into the lens paired with a camera’s own stabilization allows the user to get great, tight shots with a shallow depth of field all while being hand held.
My second favorite piece of gear is a nice fluid-head tripod. Being able to move your frame elegantly always makes for a professional composition.