what is "the heart of it all"?

[sebfish5]

No: HPFGUIDX 77404

J.K.Rowling has said there is something which is the "heart of it 
all" and that "none of the fans have guessed it yet, though they 
have skirted around it" (Newsnight interview, before order of the 
phoenix) she also said "she has laid all her clues" in a sense there 
will still be more but she has laid plenty.
 okay so 
1) What do you think this heart is, if you are that much of a god
     but, more likely
2) What, or who, do you think this "heart" revolves around?

 I think it has to be something to do with Snape, and his 
relationship with Lily and James, and his current job. Although he 
specifically states that his job is to spy on the Death Eaters. 
 I'm not saying Snape is a bad guy, infact, I think he is a good 
guy, but I think he is the centre of everything.