did anyone else pick up on the bit in slughorn's potions class about hermione being related to another wizard but when hermione blew it off then it was dropped. Seems to me that this might have been a little forshadow into hermione's bloodline and into book 7. JKR doesn't leave hints like that for no reason. Usually it is the stuff that gets passed over as not important that tends to be the most important.
I also think that Snape being the HBP will make it possible for him to continue helping Harry. And I am of the opinion that Snape is not evil and that he did what he did for 2 reasons- 1) Dumbledore told him and 2) the Unbreakable Curse with Narcissa (at which he flinched when she said the last condition) which if he didn't complete he would die.
Okay so these are just a few of my theories. I will probably have more after I re-read.
*i've cross posted so you may have already read this.