I'm going to have to go with "Buffy vs. Dracula." Far too silly, even for Buffy. No real sense of a threat, and Dracula himself was an uninspired magazine model-looking joke.
For the record, "Ted" was one of the first episodes I ever saw, and I thought it was really interesting - until he was revealed to be a robot. I still liked it, but as someone who wasn't really familiar with the Buffyverse, I was still fascinated by the concept of what would happen if a young girl in those circumstances (slaying vampires, fighting crime, etc.) had a stepfather who was like that, discovered her secret, and then she accidentally killed him. I don't know, just another tossing of two cents.
-DD