Hard to believe there will ever be a Joker to match the one performed by Ledger, @ least in the near future... Yeah I know, people say it all the times about characters and each time they find someone good or very good to portray that character that people feared won't be so good, but Ledger was so outstanding and fitted perfectly to the role, that I just can't imagine someone who could do it AS GREAT as he did!
As for villains I wanna see, well different ones obviously: Mr. Freeze, Poison Ivy (obviously NOT in the same movie!
), Riddler. But I wouldn't mind another take on Catwoman tbh!