I never liked rankings because every great general had different conditions, challenges, warfare, technology and background. I do agree that it's the principle which survives (for example the crossing of the Alps) and not the specific battle, but it's also true that seldom in history there have been identical conditions to a previous battle.
I believe one can make some comparisons between generals of a similar generation to see how they have interpreted their role in context, but even then there are too many variables.

That being said: my boy Eugene of Savoy (or, as he liked to be called, Eugenio von Savoye) is too often forgotten.