Joker is the best imo, He ant relly Anti Batman, (Ra is even a less Anti Batman than Joker, because he says the dark knight is the only man worty to marry his daughter, yikes)
Joker is insane, and has done more harm to Bat's than Ra and even Bane can dream of, Sure they can beat him by strenght, but when you cripple Barb, A freind of Batman, Kill your sidekick, and even kill one of your best freinds wife(Gordan, freind to Bruce Wayne and freind to Batman, If I was Batman and had to give up my ID to one person Gordan would be it.)
Not mention Joker has done many sick things like kidnapping 38 babies, Kidnapping the Mayor in kightfall, The Fish thing, Try to Nuke New York, Kill Robin, He has done it all.