The Loyal Opposition
Batman
The Joker

Batman Returns
The Penguin
Catwoman

Batman Forever
The Riddler
Two-Face

Batman & Robin (*shudder*)
Poison Ivy
Mr. Freeze
Bane

Batman Begins (coming soon... but not soon enough)
Ra's al-Ghul
Scarecrow

*****

Spider-Man
Green Goblin

Spider-Man 2 (tomorrow!)
Doctor Octopus "Doc Ock"

X-Men
Magneto
Mystique
Toad
Sabretooth
Senator Kelly

X2
Magneto
Mystique
Stryker