Oh, the Gift, totally. That was just.... amazing. I can't even express it, but so many characters had all these things happening... and there was Giles, with the killing Ben thing, and I totally didn't see the Buffy thing coming (or maybe I just didn't want to).
You're Welcome was good, very, very good. But it just didn't resonate with me as much as the Gift did. And I knew Cordy was going to end up dead. Not from spoileries, I just could see it coming. And I never liked "New Cordy", I didn't necessarily want her back.
And I love how even though it was the hundreth, they didn't make a big huge deal out of the gift. I don't even remember if I knew it was the hundreth until after. There was no returning cast members or anything, just a normal season finale, except for the fact that it was one of the best eps ever and wonderfully done from start to finish.