I am glad to have started such a big discussion :)
For my own part, I shall:
Obviously, for any global/member variables which are genuinely meant to be const I will put that in. That was never the question.
When I choose to create a temporary pointer, I will (try to) make the effort to put in const (e.g. const QWidget *widg = something; widg->constMethod();) where I only need to use the variable to call something const. Just as I would it it were a formal parameter to a method.
But for non-pointer simple value types, whether as local variables or formal parameters, for right or for wrong I 'm not going to cover my code with const. It's just too much to type, and I'd rather save const for where it actually matters.
Thanks to all. I'll close this in a couple of days, give y'all some more time to disagree with each other ;-)