Should flooring go in before or after kitchen cabinets?

Before, in almost every case. Running the floor first means a dishwasher or a range can be pulled out and replaced years later without meeting a lip at the edge of the opening, and it gives a continuous surface if the layout ever changes. The exception is a floating floor, which needs room to expand and should not be trapped under cabinet bases. In that case the floor stops at the cabinet run and the appliance openings are packed to height.