In any case, I can at least tell you the new working title of the presentation: it's "The Unlikely Redemption of Severus Snape".*
Also, speaking of Snape, this post goes a long way toward explaining why I find it easier and easier to understand and sympathize with Snape, whereas the more I know about Sirius, the more I want to scream and tear my hair in sheer frustration with the man. It's all about the Myers-Briggs.
Snape and I are both INTJ, so it makes perfect sense to me that he would become snappish and unpleasant when forced to deal with large groups of people all poking and prodding him to come out of his shell (indeed, his patience with the flamboyantly extroverted Dumbledore, especially over things like the Christmas cracker incident, is positively saintly in my opinion). It also makes perfect sense to me that Snape would value rational thought and argument over his feelings (or indeed anyone else's) and make most of his decisions accordingly.
But most of all I identify with Snape's very NT need to be accepted for who he is, without anyone else telling him who he ought to be or what he ought to look like. "Wash your hair, greaseball!" is NOT a good way to get an NT to conform to community standards of appearance; it's more likely to make him put extra grease in his hair for the rest of his life, or at least yours, just to prove how utterly wrong it is for society to value appearance over character. Unfortunately, as I and Snape both know, this kind of mulish disregard for the status quo also gets you bullied by the extroverted, fashionably dressed, socially adept kids at school.
Excuse me while I go and make my Snape muse a nice soothing cup of tea.
*Which is not, as one person thought, meant to say that I think Snape is unlikely to be redeemed. Actually, my view is that his redemption, contrary as it is to most people's expectations (and therefore "unlikely"), has already happened. Now it's just a matter of Snape learning to live as a redeemed person instead of continuing to dwell on his dark past (gosh, the theology just writes itself, here), and of people like Harry who have a low opinion of Snape's nature and intentions coming to realize that their view of him is at least partially wrong.