Who is your favorite villain, or villain type? Do you even have one? Does it differ from your favorite kind to use as opposed to your favorite kind to see?
When I'm GMing I don't think I have a normal or favorite type of villain that I employ. I try to hit the full mix in order to keep things moving. However, as a consumer of fiction I really like villains that I would categorize as being "Lawful Evil."
In essence, I like villains with a code they live by. A villain that has rules. That could be a hero if only the world, or problem, were a little different. The kind that are prone to making Heel/Face turns as the story goes on and you see how bad the 'bad guys' are actually going, but who sometimes don't because even if things are that bad - and they don't agree with it - they are bound by their code and their way to that side of things.
I like the drama and tension those villains bring to the table. The emotional stakes as the hero sees part of themselves in the villain, and the tragedy of how things could be so different if just one or two minor facts were set a different way.
On the other hand, while there are some individuals who do it well I find most takes on a 'Joker' esque villain who just does bad things because they're bad just kind of bores me. Jamie Foxx's character in Baby Driver is a good example of this. It's just violence, murder, and cruelty as a way of life for the sake of it, and I don't like them because villains like that shouldn't last in the worlds we're shown. They're too dangerous to everyone for it to be only the heroes trying to deal with them.
How about you?