There are a lot of earths floating around here at the minute, but none of them suited my licensing needs or practical needs, so I made my own and thought I'd share with everyone else.

I'm always wary about using anything but CC0 in projects like music videos and corporate films, as there's nowhere to credit the asset maker, so I usually avoid such things.

Anyway, the model. Simple sphere with a couple of earth textures provided by Nasa. I used the Blenderguru tutorial as a guide, but adapted it for Cycles:

http://www.blenderguru.com/videos/create-a-realistic-earth/

I've now updated the model to show the lights on the dark side of the planet. Uses the compositor to mask out the light side of earth with the glossy indirect pass, meaning the lights have been added to an additional earth model on a separate layer. I've also moved the atmosphere to a separate layer so you can adjust it individually. With all these objects making up the earth, it could be a bit tricky to actually move/rotate it without missing something, so I've added an empty to control them all.

Hope this is useful to someone out there.