As far as evidence in the form of plot hints, I'll have to go do a proper search when I'm not about to go to bed, but in the mean time... IMHumbleO, there's a strong case that Quirrel could be trying a supervillain gambit in order to make the world a better place. We know that there's a Dark Lord >somewhere<, and if it's not Quirrelmort then I think it can only be Dumbledore. Of course there is a whole spectrum of possibility here - maybe Quirrel is supervillain gambitting but is STILL the Dark Lord, maybe he isn't but Dumbles is the Dark Lord anyway, &c, &c. Also relevant is the fact that Dumbledore seems to have access to the Philosopher's stone but is not using it to save lives. I don't understand why that is, and as a result it feels like there's some major aspect of the Dumbledore-Voldemort dynamic that we're in the dark about.

Anyway, without going through and marshaling all the evidence I'm not prepared to make a bet either way on how it's all going to pan out. I do think the Dark Lord Dumbledore scenario is one that would have to be weighed in order to make such a bet, though, which is why I brought it up for discussion. I agree that that sort of ending could be done cool-ly. Whatever happens, I have a baaaaad feeling that Harry is going to find out that the world is a very, very ugly place pretty soon and I hope he comes through that without being irredeemably darkened.