There's already an official blog, this is just the polls.
After the finale airs, you can change your vote if you want to. However, do not let initial excitement cloud your actual judgement on what you thought was the best.
What I think will happen tonight
Keep in mind that absolutely no spoilers have been leaked yet for this episode so these are not spoilers. The Governor beats/tortures/rapes Andrea. The Governor then insights his people and many join him. Tyreese and Sasha decide to stay. Meanwhile at the prison, they all decide to leave. Before leaving, some of them set up a trap by opening every door inside the prison. After everyone else leaves, a few remain (probably Michonne and Daryl). When the Governor's crew gets inside, Daryl/Michonne set off the prison alarms. Walkers pour into the prison and the Governor's crew suffers heavy casualties. Daryl and Michonne leave to find Karen keeping watch at the Governor's vehicles. They capture her and meet back up with the rest of the group. The Governor and a few others get out of the prison and return to Woodbury. Milton finds Andrea, weak and bloody. He helps her out of the chair and Andrea says they have to find Rick and join back with them before it's too late. Rick, Daryl, and Michonne one to Woodbury with Karen at gunpoint. All hell breaks loose as a huge fight breaks out in Woodbury. Either Sasha, Milton, or both die. Andrea sees the Governor escaping to his apartment building and follows him with her knife in hand. Andrea finds him in his room and just beats the shit out of him. She tears off his pants and slice. She then leaves the room, assuming he'll bleed to death. Rick, Daryl, Michonne, Andrea, and Tyreese leave Woodbury. Milton, Sasha, Karen, Noah, Dr Stevens, etc may or may not be alive and may or may not go with them. At the end, either Hershel or Judith dies of causes I cannot think of. Maybe the rest of the group gets attacked by a herd?
I'm just putting this out there now, I don't think there's any way in hell this arc is ending this season.