The Hollywood Reporter has a story that this guy, Josh Pence, has been cast in The Dark Knight Rises as a young Ra's al Ghul. This has lead them to speculate that Marion Cotillard's role in the movie will be Talia al Ghul, which would make a lot of sense (but at the time of posting, THR doesn't have Talia's name spelled right (Thalia), so that kinda makes me want to not trust them).
In site-related news, don't expect a giant Ra's al Ghul post like I had for Bane and Catwoman, because hopefully you are already familiar with Ra's from Batman Begins. I will probably do one for Talia if this rumor is confirmed.
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.