I always leave it in 1st gear at a stop. When holding the clutch completely open there isn't that much strain on the diaphragm spring, cause it is in a second state of rest. There is almost no wear in this case.
When shifting to neutral and back to first at a red light you're using more components, and those components are more vital and expensive. Hence I always leave it in first with the clutch disengaged of course
. The only time when I would put it in neutral is if I would have a lot of pain in the muscles of my leg and I would have to keep the car to a halt for a long time.