Id go with Angelus. Legendary.
I think it was because he had personal ties with Buffy and the scoobies that made him even better.
I mean, Glory and the Mayor etc, were just baddies with a mission, who would have done what they did with or without Buffy being around.
But Angelus, he was not only created by Buffy, but had a personal relationship with her.
The way he went after Jenny too, just because he knew how much it would hurt the scoobies.
That to me, makes him the most evil and sinister of all the bad guys.
I think it was because he had personal ties with Buffy and the scoobies that made him even better.
I mean, Glory and the Mayor etc, were just baddies with a mission, who would have done what they did with or without Buffy being around.
But Angelus, he was not only created by Buffy, but had a personal relationship with her.
The way he went after Jenny too, just because he knew how much it would hurt the scoobies.
That to me, makes him the most evil and sinister of all the bad guys.