Joe Coyne (get it?) works hard to earn just pennies, gets fired for pitching pennies on the job, and when he tries becoming a thief he robs a cash register full of only pennies. In jail, he gives a truly impressive villainous rant: "When I get out, I'll get back at coppers and pennies! I'll fight coppers - with pennies! Every job I pull will involve pennies! My crime symbol will be pennies!" Committing penny-themed crimes, stealing antique penny banks and a rare one-cent stamp, the Penny Plunderer is mostly remembered as the man responsible for the giant penny that can be seen in the Batcave to this day.
Pros: Although the animated series had a much more clever origin (Two-Face strapped Batman and Robin to a giant penny which he launched into the air, given them a 50/50 shot at being crushed, but they landed face up), the Penny Plunderer's giant penny has appeared in hundreds of comics, so even though he only appeared the one time, he's somewhat legendary (his appearance collected here, the story ends with him being sentenced to death, which seems very un-Batman-ly).
Cons: Pennies 60 years ago weren't that much money, but with inflation they're practically worthless.
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.