I nominate
Consciences and Consequences because it's great to see another facet of these characters as they deal with something truly unimaginable. It's a very clear marker in their future path, and a great plot thread, to boot.
I also nominate
The Way I Feel because despite it being only two posts in, Nathaniel's current state of mind is sure to make for an explosive thread--and not in a good way.
And finally, I nominate
Cut To the Quick because it's a thoughtful (if painful) look at past hurts, insecurities, and a wide range of emotions. Difficult to work through in the best of times, harder to share with someone else. It's a touching thread and a great pairing of characters.