(1)Minerva McGonagall
(16)Bartemius "Barty" Crouch Jr.
McGonagall to me represents all kinds of lost potential. I remember two influential essays before book 7 comes out. One was "Snape loves Lilly", where we figured out basically the exact contents of the Snape's Memories chapter (right down to stuff like Snape was the one to tell Lilly about Dementors and Azkaban). The other essay was "McGonagall is a death eater". And it makes all kinds of sense--despite being in the order of the phoenix, she misses damn near every major battle for some excuse or another. An hour after Dumbledore died, she gets Harry alone in the headmaster's office and starts grilling him for information (and Harry refuses). And if you go back to the introductory chapter in book 1...instead of celebrating, she's following a lead, expressing distain at how muggle the Dursleys are, and Dumbledore is quite guarded in what information he shares with her.
So...lost potential there. As is, she's a generically strict teacher, who can nonetheless be indulgent, and fights with the good guys but for no explained reason nobody trusts her enough to share inner circle information.
In the mean time, Barty Crouch Jr is pretty awesome. There's an open question, I suppose, on whether you should count fake-Moody towards Barty Crouch Jr, and I'd argue that you should--at least at some level. His personality is subtly different from real Moody. Various things he says have double-meaning, like when he taunts Snape about his dark mark. (Bear in mind, at this point Sirius doesn't even know what a dark mark is, despite spending three years listening to other prisoners mutter in Azkaban, and presumably the ministry doesn't either because they locked Sirius up). He's also much more flattering--like he spontaneously suggests to Harry that Harry might want to be an Auror. It strikes me that the real Moody might do something like say "oh, well, I've got several old photographs of aurors, why don't I describe the gruesome way in which each of them died? Real treat for you, eh?" I also like how, after describing how using an unforgivable curse on a human will land you in Azkaban, he starts Imperius cursing the students for practice. Somehow I don't expect the real Moody would be like "hey harry, want to practice breaking the Imperius curse after supper?"
And of course, on top of his interesting acting skills, and subtle differences from real Moody, he's also by far the most competent death eater. (Or most competent loyal death eater, I guess; Snape is pretty good too).
(8)Quirinus Quirrell
(9)Rufus Scrimgeour
"I shouldn't have said that," said Scrimgeour quickly. "It was tactless —" "No, it was honest," said Harry. "One of the only honest things you've said to me. You don't care whether I live or die, but you do care that I help you convince everyone you're winning the war against Voldemort. I haven't forgotten, Minister...." He raised his right fist. There, shining white on the back of his cold hand, were the scars which Dolores Umbridge had forced him to carve into his own flesh: I must not tell lies.
Scrimgeour, frankly, benefits from showing up in book 6, when Rowling's writing is in turbo kickass mode (whereas Quirrell only shows up in book 1). But he's also an interesting character--someone on the same side of the war as Harry, who is clearly competent, and legitimately wants to take down Voldemort, and yet is clearly an antagonist.
(4k check)
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Cats land on their feet. Toast lands peanut butter side down. A cat with toast strapped to its back will hover above the ground in a state of quantum indecision