No, this isn't a list of, a rant about, or a set of guidelines on how to build and play one of the most difficult, but essential elements in a plot; an antagonist, or more commonly, a "villain."
Instead, this is an opinion poll regarding these difficult characters. A very simple one, and yet not without its intricacies:
What is your favorite "design" of villain? What kinds of things in specific do you like in villains; this extends to basic design in regards to appearance and personality, plots they execute and the method they go about these, and yes, relevant fighting abilities (if the villain is meant to fight in some way, be it directly, indirectly through minions and lieutenants, or both(albeit not always simultaneously)). You may make answers as general or detailed as you wish; this is simply an opinion poll.