Several. So many it's hard to even pick one. I guess for antagonists though, I'll always tend to like the descending order of evil, and subverting the shit out of it. That is, think stuff like...
- The honourable second in command of the big bad, who gives you a fair fight... Just because he sincerely believes he's invincible and wants to see you suffer more.
- The man who sacrifices hundreds of children in horrifyingly painful experiments... Because he sincerely does want to cure every disease that afflicts children on Earth, and thinks a few hundred dead now is worth a few thousand saved later.
- The righteous crusader who kills in the name of their ideology--which promotes peace and tolerance, instead of war. (Not necessarily religious, but often is just due to the nature of faith.)
Oh, and my villains nearly always believe themselves to be right. To me, that's what makes a villain truly believable no matter how ridiculous his or her schemes may be: That they have that
spark, that deep desire to prove how they're right and everyone else is wrong. Moral absolutists or the righteous crusaders, or the "needs justify the ends" bastards. Some can be redeemed, some can't.
All I know is: A villain that knows what they're doing is wrong and does it anyway for the lulz, is a boring villain with no motivation beyond random chaos. The Joker isn't interesting because he's randumb--he's interesting because his entire life serves as an antithesis to Batman: His every villainous machination is built around fucking with Batman, doing things he know will hurt Batman.
This easily beats anything Heath Ledger's Joker did and evokes more emotion from the audience, no matter how well Heath Ledger acted out his part (and he acted it out
damn well just so we're clear), because Hamill Joker did something that Ledger Joker didn't: He
fucked up Batman's mind and
horribly hurt someone that Batman was closest to. Not with something even as simple as death, but with something even worse than death.
I aim to play villains like that against my players. I aim to make them do horrible, terrible things that the players
care about to some degree. Even if it takes a while to develop them, it's always better to play a the villain who believes he is absolutely in the right, or who acts out on a carnal nature they cannot control, than play a villain who blows shit up because he can. A villain who murders someone you care for is a thousand times more effective than a villain who murders ten thousand people you never met.