Okay, so this is a post that occurred to me as a subject recently, when noting the love everyone has of Heath Ledger as the Joker, often preaching that he is a better Clown Prince of Crime than Jack Nicholson (something I respectfully disagree with; I will always prefer Nicholson, though Mark Hamill's vocal performance trumps them both; I challenge you to find someone who saw the Batman Beyond movie who didn't get a chill when they heard that laugh...)
Anyway, it got me to thinking; what makes a good villain? As both a fanfiction writer and a budding actor/writer/director, I wonder about this from time to time anyway, but this is the first time I've considered the things that make it.
First of all, as many people will say; a good villain isn't a villain in his/her eyes. (S)He is the hero of his/her own story. For example, to continue on the line I went down earlier, the Joker doesn't see himself as evil; he is an admitted lunatic, but he doesn't consider himself evil. Another prime example is the Leader from the Hulk comics; he actually sees Bruce Banner/The Hulk as keeping him from what is his right, that being the power of the Hulk and control of the world, and what he does is in aid of getting that power.
Of course, in kids movies and pantomimes, you'll often see villains that preach how they love being "bad" or "evil," but this doesn't inherently make them a badly written villain; it just means they're written for the audience, with a level of two dimensional thinking required of the role.
Another thing that makes a good villain; being a true equal for the protagonist. An example of this is General Zod in the Superman comics and movies; he possesses all the powers of Superman, along with the tactical mind of a military leader, and advanced hand to hand combat training, as well as the lack of care for casualties Superman has; he's able to use this to defeat Superman, as we see in Superman II, and he makes Superman break possibly the only rule he and Batman share in Man of Steel by threatening a family with his heat vision, forcing Superman to kill him by snapping his neck.
Of course, equal doesn't have to mean physically. Lex Luthor is vastly inferior to Superman physically, but makes up for it with his massive intelligence, to the point that he can outclass the Man of Steel. A little Kryptonite always helps too!
Then there's the other idea; a superior villain to the hero. Bane, Venom, Darth Vader, they and many others all fit this mold. Note, I'm referring to comic book Bane (who was mostly portrayed in Dark Knight Rises in an accurate manner, barring one or two issues, such as the mask rather than his traditional Mexican Wrestler with a chemical tank look) rather than Batman & Robin Bane (about whom, the less said, the better); in the books, he was Batman's intellectual equal at the very least, whilst being far superior to him equally; he was smart enough to instigate a mass break out of all of Batman's rogues, wait until the Dark Knight was battered and beaten, before confronting Batman in the Batcave! That's right, he brought the smack down to Batman on his home turf, and he broke Batman's back (as seen in Dark Knight Rises; that image is straight from the first volume of the Knightfall arc, and was the best thing about Dark Knight Rises) before leaving him there.
Another key point about a good villain; sometimes, they don't even need to meet the hero for more than brief encounters. Let's look at some examples of this; Professor Moriarty, Ernst Stavro Blofeld and Hush, to name a few. All of these are characters who seldom show up themselves, but when they do, their presence has long been felt before. They aren't the kind of villains who feel the need to shove girlfriends into refrigerators (though Blofeld's assassination of Bond's wife on their wedding day is a close second to that image from the 1990's Green Lantern comics).
An even better example of this is Khan in Star Trek II; he and Kirk never come face to face for the duration of the film; yes they speak over communications channels, and see each other across view screens, but they are literally miles apart at the time. Khan is an example of everything on this list; he's Kirk's intellectual and physical superior (though it was an anti-climax when he was defeated by his own "two dimensional thinking" although, given he was from the 20th Century, so used to naval combat involving sailing ships rather than starships, that does make sense) and he doesn't see himself as a villain. Quite the contrary; he sees Kirk as the villain, for marooning him and his crew on Ceti Alpha V, with his sole motivation being to avenge the deaths of his wife and comrades.
So, to sum up, what makes a good villain? Essentially, being Khan from Star Trek. Haha I kid; a good villain is a three dimensional character, someone with their motivations clear, whether their goals be self serving or even relatively selfless (Lex Luthor being an example of both; he perceives Superman as the first of an alien vanguard, whilst it's also a matter of Superman threatening his own position as most powerful man in the world. Clearly, he forgets about Bruce Wayne and Oliver Queen when working things out...). They may not be inherrenntly evil; instead, they simply want a change effected.
In short, a good villain isn't a pantomime villain, unless you're watching a pantomime, of course. A good villain is a character who supports their part of the plot, is able to carry just as much of it as the hero, and who has a rich and varied story. Or is Doomsday, because he killed Superman for gods' sake!
Kidding aside, well, a good villain is just a good character. Same as any other. They just have a tendency to be more fun.