I just saw the new Batman movie, "The Dark Knight". Like every reviewer I have seen, I thought the movie was good. But what impressed me most about the movie was the character of the Joker. I suppose it was a combination of the character himself, the writing in this movie and the performance by Heath Ledger that combined to make him an excellent villain.
Of course the movie was meant to raise questions of morality and of what really is good or evil. The best movies are not just a series of explosions but also lend to these kinds of philosophical... yes, even, theological questions. And with the Joker I think they were tapping into a depiction of the ultimate villain - Satan himself.
Notice that the Joker wasn't so much out for his own gain, but to bring down good people - to make them like him. He puts them into situations with great temptation to do wrong. (Interesting, too, is how the movie treats man's response to such temptation - sometimes giving in, sometimes rising to conquer it).
Also - though he repeatedly claimed to be a "man of his word", he was full of deceipt and did, in fact, lie (for instance, there were two stories about how he got his scars...). Compare this with the Father of Lies, who often uses a little truth to support his own purposes.
Even the whole clown persona of the Joker - an expression of something good gone terribly wrong - finds a paralell in the Devil who was once an angel of light. The sick smile is not from true joy but from blasphemous laughter at God and good.
Of course, the Joker's origins are shrouded in mystery. He simply appears on the scene without a history or reason. So too Satan, who simply appears in the Garden without explanation.
The Joker begins with a promise to serve and work for the crime bosses, but then "takes over" the entire city. So our enemy makes many promises, but what he really wants is control. And to a large extent, the "Prince of This World" has gotten it.
Add to that the Joker's resilience, conniving genius, and manipulative powers - and the picture of evil is really quite exquisite.
Of course, there are various Christ figures in the movie too - Batman being most obvious. Actually, there have been many other movies with better Christ figures. But I haven't seen this good of a villain in quite a while.