Not on the list but for me John Lyall.
Nice try Ad O, but not really going to cut it. We all have the favourite manager for our club, but that doesn't mean they have 'greatness' beyond that myopic view.
So as a Watford fan I've huge respect for Graham Taylor - a phenomenal manager in terms of the achievement of bringing a team from the lower divisions to being FA cup finalists, runners up in the first division, Europe and managing England. But he's an also ran in the company of the greats whose success isn't relative, but absolute.
I have a friend who is an Ipswich fan and he, of course, went for Bobby Robson - and for all his achievements, his Ipswich-coloured blinkers remain all too obvious.
Best for your club, doesn't equate to the best.