Sorry, I see only few of these guys as really great villains. Probably `cause I haven`t read stories from alot of them.
Public domain Loki didn`t make the list (I qualify this version as the combination of all his versions). Buhuu! Well, at least Marvel Loki did.
He seems to be an interesting character. In 616 and MC2-universes, that is. Too bad I haven`t read Spider-girl. Oh, and by the way, isn`t that info of him a bit spoilerish? Sorry, to say that, but it is.
But anyway, it`s nice that you tryed to include a not-so-often-seen villain to the list.