I vote for Steve Dobson for the BDA. His death, while being just as meaningless as the others, still managed to give the island's resident psycho the message that, despite what she may think, her power over people is still limited. That he managed to be at peace with himself while dying makes it even better. Regarding the writing, the fact the way he (almost) managed to escape death by her hand was foreshadowed, namely how the sickle had torn through his bag, was clever and tied his actions before his death together with his actions at the time of his death. And the way it ended, in the middle of a thought, was great. He lived until he died, not giving himself to death until he was truly gone.
For the BKA, I vote for Kimiko Kao. A sympathetic character, for whom, despite her being a murderer twice over before this one, the kill didn't push her out of our sympathy, but, in a very clever way, enhanced it. A good deal of credit must go to Ruggahissy for this as well, whose handling of Caleb Diamond accounts for at least half of the tragedy that this incident produced and was my second choice for BDA.
Plus, the bastard in me wants her to win this and have it announced again, with commentary. I'm curious what that would do to her sanity.