Resurfacing rotors is always a good idea when replacing pads. If you are a leadfoot then it's an even better idea. It promotes proper pad seating. I know my rotors sometimes get glazed over from very aggressive on ramp/off ramp behaviour and cutting them can sometimes remove that surface quality.
You should see brakes from showroom stock cars! New pads and rotors after every race event. They look like crap when done and no metal to metal contact.