Season 3 Finale, Fan Theories

Some interesting fan theories of the season finale:

• Locke's father was hiding in Christian Shephard's casket, hence no body when Jack smashed the coffin, and that's how he ended up on the island.
• Christian Shephard is Jacob
• The "Vincent is the Monster" theory builds
• Jack is in on Ben's plan without Juliet knowing. We think he's an Other, but instead he double-crosses Ben
• Penny makes it to the island somehow, but Desmond ends up dying to save her
• The finale will end showing someone with four toes
• With the magnetic anomolly discharged, Dharma can find the island again and sends in their troops
  

My favorite fan theory of the season finale, from a dude named Raymond:

End scene: The Losties have won the Battle for the Beach largely because while Juliet served as a Trojan Horse for The Others, Locke served the same function for The Losties. Ben has been captured. He's injured, bug-eyed and bloody.

Locke tells Jack that Ben has Jacob's list in his possession.

Locke: Let's get a look and see if we can make some sense of it.

Jack: Give me the list, Ben. Now.

Ben: Are you sure, Jack? Are you sure you want to see it? Be careful what you wish for.

Jack: No more mind games, Ben, just give me the list.

Ben: Alright, Jack, you're the boss, you're the leader. Here it is.

Jack takes the list. His face goes white.

Locke: It's alright, Jack. It doesn't matter if your name isn't on it, we don't even know what it means. It probably means nothing.

Jack: No, it's not that.

Locke: What then, what?

Jack: This is my handwriting.