As The Dark Knight mounts its record-breaking box office run, talk of future sequels has already reached a fever pitch. But which foes might Batman face in a potential follow-up? Following in the footsteps of Heath Ledger's terrifying turn as the Joker would be an unenviable task for any actor, but the real challenge could lie with director Christopher Nolan and his brother/writing partner Jonathan. A peek at the remaining adversaries in Batman's legendary "Rogue's Gallery" reveals a less-than-appealing cast of cartoonish, over-the-top characters ill-suited for the darker, more realistic vision of the Caped Crusader established in Batman Begins and The Dark Knight. Any characters plucked from remaining ranks of Batman villains would almost certainly have to be reinvented to fit the Nolan mold: that is, no supernatural abilities, no outsized physical proportions and no preposterous origin stories. Here's a list of foes with a shot at making the cut.
A smooth-talking misanthrope with severe obsessive-compulsive tendencies, the Riddler taunts his pursuers with puzzles and devises elaborate deathtraps for his victims.
Previously portrayed on-screen by: Frank Gorshin, John Astin, Jim Carrey
Could be re-made in the Nolan mold as: a modern-day version of the Zodiac Killer.
Potential actors: Guy Pearce, Ewan McGregor, Ryan Gosling
A waddling, corpulent gent with a large, beak-like nose, the Penguin is best known for pioneering the use of umbrellas as weapons.
Previously portrayed on-screen by: Burgess Meredith, Danny DeVito
Could be re-made in the Nolan mold as: a dapper, diminutive mob boss with a serious bird fetish and a Napoleon Complex.
Potential actors: Jack Black, Philip Seymour Hoffman
a sultry former botanist, Poison Ivy can communicate with plants, is immune to all poisons and secretes a toxin that allows her to literally kill a person with a kiss.
Previously portrayed on-screen by: Uma Thurman
Could be re-made in the Nolan mold as: An environmental zealot turned eco-terrorist -- like the Unabomber, only more creative (and female).
Potential actors: Hilary Swank, Angelina Jolie
an expert in field of mind control, the demented, unstable Mad Hatter manipulates others with the aid of a device embedded in the brim of his hat. Inspired by the Lewis Carrol's Alice in Wonderland character.
Previously portrayed on-screen by: David Wayne
Could be re-made in the Nolan mold as: A renegade Wayne Enterprises employee who utilizes nanotechnology to scramble the brains of his foes.
Possible actors: Daniel Day-Lewis, Jude Law, Joaquin Phoenix
A powerful mob boss with aristocratic roots similar to those of childhood friend Bruce Wayne, his trademark fashion accessory is a mask carved from the ebony coffin of his mother.
Previously portrayed on-screen by: Nobody
Could be re-made in the Nolan mold as: The Black Mask is rumored to have made an appearance in early drafts of The Dark Knight, as a would-be industrialist who turns to crime after his company is absorbed by rival Wayne Enterprises.
Potential actors: Viggo Mortensen, Russell Crowe, Hugh Jackman (if Marvel lets him)
Bane - A steroid-pumped madman who broke the back of the comic book Batman in the early '90s. Bane's forgettable cameo in 1997's disastrous Batman & Robin broke the back of his movie career.
Killer Croc - Batman's reptilian adversary has been a regular fixture of the comic in recent years. His sci-fi features and unimaginative name, however, make him a poor candidate for Nolan's universe.
Mr. Freeze - Like Bane, Mr. Freeze is a Joel Schumacher casualty. His character is probably too preposterous for Nolan anyway.
Clayface - A shapeshifter who can alter his appearance into any form he chooses, Clayface is too sci-fi (and too similar to the Spider-Man 3 villain Sandman) for this version of Batman.
Catwoman - With memories of Halle Berry's franchise-killing spin-off still fresh in fans' minds, don't expect Catwoman to be prowling around Nolan's Gotham City anytime soon.
Who do you think should be the villain in Batman 3? Leave us a comment below.