I chose Gul Dukat, The Borg Queen, and Soran. Dukat (even before he became a puppet to the Pah-wraiths and became true evil) was responsible for countless deaths and atrocities in the name of his people. Soran destroyed a planet for his own selfish personal gain and then left the weapon in the hands of the Duras sisters who would have reeked havoc across the alpha quadrant (they'll attack the Romulans that betrayed them, the Humans that defied them, and even the other Klingons that stood against them). The Borg may be mindless drones but the Queen who directs them would stop at nothing to assimilate everyone in the galaxy and she wouldn't even hesitate to sacrifice her own drones just to prove a point.
Had to go with Annorax, oddly enough. VOY had its problems but he was one of the best Trek villains period, chillingly monstrous with a psychologically realistic core, and more truly heinous in the larger sense than Khan. My first pick would have been Kivas Fajo -- am I going to cause angst by asking "why no Kivas Fajo"? His is a much more personal, intimate heinousness and in some ways more creepy and effective because of that; he's no world-destroying super-baddie, just a greedy, petty, pretentious sociopath, and he's all the more memorable for that.
His Assholiness, Gul Dukat. Her Hineyness, the Borg Queen. And Soran, for being a selfish bastard. My thanks to the film Flesh Gordon for providing the titles of address.
Well, I'm always accepting input in my poll prep thread. http://www.trekbbs.com/showthread.php?t=230098 But there are people on the list that's far worse. Is it just for recognition?
I shoulda checked in, for sure. For me, heinousness is a matter of style as much as scale. And for my money a lot of the big world / galaxy-smashers on the list hail from rather too moustache-twirling places on the Villain Spectrum to really make the grade (cf. House of Duras). Never much cared for the way the Borg Queen concept turned the Borg (at least poetically) into a kind of insect hive analogy, either, though Alice Krige is awesome.
The Borg Queen is trailing behind and Khan and Dukat are neck and neck. I still think Soran should be in the top 3 but I am curious who'll take the lead.
I voted for.. The Sphere Builders: while not exactly having any charisma their plan was absolutely heinous in that it spread through space and would eventually poison and destroy entire sectors and planets. The Borg Queen: She makes choices. She is exerts her own ideology upon thousands and thousands of worlds. Dukat: Insane and insanely dangerous who rose above being a badass fucker in Cardassian administration to playing with literal fire.