It's DVD/Blu Ray launch day today. Check out slashfilm for all the details on the various versions with different promotional junk from different stores.
Also, tomorrow the trade paperback for Joker's Asylum comes out. It was a pretty hit or miss series for me, with one shot stories featuring villains like Two-Face, Scarecrow, and Poison Ivy, but I enjoyed the Penguin issue written by Scalped's Jason Aaron enough that I'd cautiously recommend the trade to fans of Batman's enemies.
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.