[SPOILER="speculation/spoiler"]
Batwoman = commissionar gordons daughter right? or is that catwoman?
i REALLY hope they dont introduce any of the side characters.. ie: robin.
the joker may still be alive, but they won't bring him back because duh ledger is dead

scarecrow is still alive he had all but 10 minutes in thsi movie
two-face might be alive, not sure what else he will bring to the table tho.
penguin, mr freeze etc. are just too out there (unless they simplify them)
poison ivy, harlee quin catwoman: maybe.. women dont make very good villains imo.

h:
Clayface :ugh: never liked that whole series..
riddler: if they can get somebody to play the riddler as well as heath ledger played joker, then i think we have a winner
[/SPOILER]
Don't think this needs spoiler tags.
In the first movie they showed an escapee from Arkham who may not have been recognized except by people who read the comics. There was a dude walking around with hatch marks etched in his skin. His name is Zsasz .. and his story in the comics is deffinatly dark enough for Nolan's version.
Not that he could be the MAIN villian.. or anyhing. But he's deffinatly fucked up enough to have a larger part.