I bet those Diablos (all black) are great on hot sunny days on the slabs eh?
Whatever shoes fit you comfortably will be good all day shoes. I had high hopes for the scarpa marathons, but they don't fit me very well. I have a narrow foot.
My boreal aces (now rotten and retired) were probably the best all day shoe I've used.
If they still made the Huecos with the heel padding (like MisterE has), I think that would be a great shoe if they fit you.