Battlestar Galactica
Huge kudos go to the writers for last week's episode. Sure, it was a massive infodump, but they got themselves out of every corner I thought they had painted themselves into.

Why are there Cylons 1-6 and 8? 7 was (presumably) destroyed.
Why did the Cylons end the first war? They were bribed.
Why was there such a jump in Cylon technology between the wars? They were given it.
Why don't the 5 have memories of the past? They were wiped by Cavil.
Why do the Cylons have a god? It makes them human.
Ellen's appearance in the fleet was nicely retconned by saying Cavil wanted her to stay alive. Likewise, there's an explanation for the rest of them surviving as well.