We're uncontrollably worked up over Harry Potter and the Deathly Hallows, and all month we'll surf the Potter fan sites, scan the message boards, and read the tie-in books to argue the biggest pre-publication speculative debates.
Theory: Severus Snape once loved Lily Potter, Harry's mother, and that love will play a major role in the final book.
The argument for: There's not much evidence at all for this, but many fans' desire to see Snape as an Austenian conflicted hero has most vividly manifested itself in this theory, which posits a schoolboy crush (or more) for old Severus. Notably, Dumbledore tells Harry that Snape's decision to tell Voldemort about the secret prophecy, which led to Harry's parents' death, is Snape's greatest sorrow in life. Why? Snape hated James Potter, as he wastes no opportunity to tell Harry. But he never tells Harry anything about Lily…
The argument against: Severus Snape wouldn't recognize love if it bit him on the end of his greasy, hooked nose.
Our take: This is one totally unsubstantiated theory that we completely buy. All along we've been told that Harry looks like his father but has his mother's eyes. How better to explain Snape's tortured emotions toward Harry — he despises him but protects him over and over — than if he sees the eyes of the woman he loved (and betrayed) staring out of the face of the young man he hated?
Wade into the debate: Mugglenet has shut down its message boards in anticipation of Book Seven's publication, but this essay by Rachel LaBozetta makes the case for Snape's love of Lily, and the (less excitable) posters at the Leaky Cauldron discuss all things Snape here.