Busy with work, so I haven't been able to put up any characters in a couple days, but just FYI, the animated Batman: The Brave and The Bold premieres on the Cartoon Network tonight at 8. The series looks very kid-friendly, Dick Sprang style art but with modern-looking action, and feature Batman teaming up with a different hero every week, starting with the Blue Beetle tonight (I'm not sure if it's Ted Kord or Jaime Reyes, but Blue Beetle is cool either way). Check out the Cartoon Network site for more.
After The Scarecrow, Ra's Al Ghul, The Joker, and Two-Face, who should be Batman's next enemy in the Batman Begins/The Dark Knight series? Well, as of now we know that Tom Hardy will play Bane and Anne Hathaway will play Catwoman.
Check out the master list for all the villains covered. I've pretty much run out by now. Obviously, there are more Batman villains, but not any of significance that I know of. As of February 2009, no one is confirmed as a villain. Not the Johnny Depp Riddler, not Phillip Seymour Hoffman Penguin, nobody.