harry potter 6 title ruminations

So everyone knows by now that #6 is "HP and the Half-Blood Prince." And so, who is this HBP? We know from Ms. Rowling herself that it is not Harry and not Tom Riddle/Voldemort. But here's food for thought:

Candidates for the HBP:

1. Neville Longbottom. I think it's assumed that Sybil Trelawney's predictions are going to play a role in the eventual downfall of Voldie, and that that event will no doubt occur in Book 7. Rowling has gone on the record saying that Book 6 and Book 7 are really two halves of one story, so 6 and the HBP will no doubt be instrumental in setting up the last battle. If Sybil is to be believed, and Harry may or may not die when Voldemort does, then the vanquisher is Neville. We know little about his background, other than the fact that his parents are crazy and once were Aurors. I've always had a soft spot for the little guy and he seems to be getting the clumsiness under control in OotP. Maybe he grows up in Book 6 to become the strong, silent, heartthrob? Like a wizard Clark Kent?

2. Severus Snape. As my mother keeps telling me, "By the end of this, he'll come out smelling like roses." And so he should, since he's so cool. ;) (Says the totally biased Snape-fan.) But like Neville, we know nothing of his background, but those deep dark secrets are coming slowly to light, also see OotP. (Though I bet he's a pure-blood- or did I read that somewhere? He's sneaky though, I can see him persuading people that he is one thing and not another.) Wishful thinking for more Snape involvement in the books...

3. A yet-to-be-introduced character. The new DADA professor, perhaps?

4. Possibly someone from Sirius' past, family, or Sirius himself. (There are those who believe that he is still alive- wouldn't you think anything was possible in the Ministry of the Mysteries?)

5. "Prince" implies a dimunitive, a second in command to the king. Peter Pettigrew, then?? Switches sides once again?

Then there's always the Anthem Book Blog's idea. ;P