I don't sit at a red light in gear. IAM and RoSPA may not like the idea of selecting neutral before you've actually stopped, but actually I do that a lot .... those last few feet of travel I'm normally in neutral and putting my right foot on the floor.
I do agree that there is a place for being aware of what's happening behind you when you're the last in the queue at the lights. I try not to stop bang in the middle of somebodies number plate, but rather in their off side wheel track so I have a natural escape route if I need it. In thirty years I've never been rear ended, but I guess I do subconsciously plan for it. (One of the reasons why many bikers think the hendon Shuffle is pants and that they'd rather sit covering their gear lever). So for me it's neutral, but left foot ready to go and half an eye in mirrors looking for the next bloke to join the queue.
On fast roads (motorways / dual carriageways) where there's sporadic stationary traffic, the risk of a small pile up is actually quite high. I would say that daily, there is a three car shunt on the approach to the dartford river crossing. It's probably more relevant to car driving (a bike is going to go for the gap..) but I very much think about being shunted in those motorway scenarios. I always leave a good twenty yards or so between me and the car in front until I see the bod behind me reacting and slowing down.