Batman- 1 villian: Joker
Batman Returns- 1 villian: Penguin, 1 Enigma: Catwoman (who seemed to be with and against Batman at different times throughout the movie, from what I remember)
Batman Forever- 2 villians: Two-Face and Riddler
Batman and Robin- 3 villians: Dr. Freeze, Poison Ivy, Bane (must atmit, I never saw this one, so I don't know how significant Bane was in the plot)
More villians <> better movie