My companies policy is flaps 40 for all landings. We must engage flap 40 by 1000ft. Personally i find it easier to land and control the aircraft with a flaps 30.
Reason being: The extra lift created from flap 40 gives you a high nose up attitude and causes a baloon effect just as you flare.
Flap 40 helps on short runways but is seriously not needed. Flap 30 is fine.