Name five characters who would make good supervillains (actual current supervillains excluded).

I'm assuming this also means no reformed supervillains, which excludes the likes of Emma Frost and no we-don't-know-yet-whether-they-are characters, either (this excludes you, Mark Milton). So, let's see:

1) Laura Roslin (Battlestar Galactica). Is already scary as hell as a ruthless sort of good person in a very morally grey world. Would completely take over the universe if she went dark side and didn't care about the body count any longer. Would also make everyone raising objections to her rule look like the bad guys, no matter how right they are.

2) Elizabeth Swann (Pirates of the Caribean). Mind you, if you read some posts, you'd think she's there already... Anyway: Elizabeth would not take over the universe, or even the Americas, but she'd be the most feared Pirate King there ever was (as opposed to "just" being one of the most respected), and of course she'd frame someone else to hang for her once the time of the pirates does come to an end.

3) Peter Petrelli (Heroes). I'm with yahtzee63 on that one. (See also: sparky77's "6e" universe.) Few things are more dangerous than emotionally unstable idealists going crazy, and this one isn't just unkillable but also equipped with all sorts of powers. Mind you, I can't see even Evil!Peter being the kind of supervillain who is after ruling the planet, because Peter might be crazy already, but he's genuinenly not interested in leading. But he'd be perfectly capable of being a supervillain who destroys the planet in a gigantic emotional temper tantrum. And/or subjugates on someone else's behest.

4) Delenn (Babylon 5). Back to the schemer/ruling the universe type of supervillain. Delenn already came close to wiping out humanity and managed to make anyone bringing that up afterwards look like a big meanie. Not to mention that even as a good guy, she's convinced of being chosen and manages to become President of an interstellar Alliance directly after her husband, whom she manoeuvred in that position to begin with, had the job. (Hillary can only dream of being so efficient!) Take away her sense of guilt and occasional qualms, and all would love her and despair. (Well, I'm not sure about the "despair"part. I see Evil!Delenn ruling the galaxy with Neroon and Lennier as concubines...)

5) Octavian, aka Augustus (history, actually, but I'm thinking specifically of the Rome version, as opposed to, say, the I, Claudius one). He'd be incredibly efficient at ruling any given country/world/galaxy, depending on which time frame you'd put him in, would destroy any opposition, but he'd also be the most joyless supervillain around. (Again, not true for other versions of Augustus; one might argue with Graves' father-knows-best interpretation, but his Augustus did know how to enjoy himself.) You could count on him avoiding all the Evil Overlord mistakes, but I'm sure his Trusted Lieutenants would secretly think that maybe a "death is too good for my enemies" rant once in a while or perhaps a chuckle or two would make the man less frighteningly efficient and more relatable to...