The Joker is definitely the best Bat-Villain. Scariest concept, craziest plots, most insidious. Plus his most recent defeat of Batman from the recent movie was so all encompassing it was amazing. Killed his girl and destroyed the "white knight" of Gotham, while forcing Bats to pit himself against Gothams finest.
Bats vs Spidey? No contest. Bats punked Superman in the Dark Knight comic series. Spidey would get his web covered backside beat.
Lastly someone to add to the all time baddest bad dude argument would be Galactus. All powerful, planet destroying force of nature, that also enslaves members of the races that he demolishes. Badass
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