I'd like to add my own option here. I think the best villien is rightious and perswasive.
I beliive that a villain shouldn't really be a villain at all.
Attila the Hun comes to mind. He weilded the "Join us or die" trait. That's a pritty great bargoning chip. In fact, he only stopped his crusaids on rome because pope Leo I told him too. I belive he was the greatest villain of all time.
Skipping ahead, a more recent villain was Hitler. Now, not to be kicking up dust or making people mad, but Hitler was good to his people. He made them all equil, gave them all the same car, house, etc. This made him a good villian because his people would follow him, as he was a "hero" to them.
So, there you go.