Chosen. By far. And I love both episodes, but Chosen wins because of the great ending. I think it was the perfect ending and it conveyed what Joss wanted to uhhh...convey, the whole year. This girl has power. I loved when Buffy told the First to get out of her face. IMO, that was how the First died. Buffy wasn't afraid of it, like Faith and Wood said, it makes you afraid.
Anywho, enough incoherent ramblings, I loved both, but I liked CHosen better and despite being rather anti-clamatic, it had the perfect ending.