We've certainly had some doozies. (A sex gas alien? Why do you do this to me Torchwood. WHY?)
I'm not sure I really have a favorite villain. The majority of my favorite episodes actually had human villains (or no villains at all).
Though, John Hart was pretty interesting, especially in the season two finale. I found him to be a bit unbelievable in the premiere. I also liked the cannibals.
Hmm... I guess Torchwood doesn't really have any super iconic enemies, except perhaps the 456. And I really can't get behind a species that is constantly barfing in the middle of a conversation, at least the Daleks are cute little pepperpot look-a-likes. 3nodding

