If you want the 'Planet Earth' touch, the majesty and beauty of satellite imagery in your film then you can use Blue Marble from Nasa, an archive of free-to-use extremely high resolution images of the Earth. The very images that helped the BBC generate some of the memorable shots that made 'Planet Earth' so spectacular.
To view the full resolution you would need a monitor as big as your house (1 thousand million mpixels) so I think the quality is fit for most purposes! However, you will need a mighty machine and photoshop 8 to even stand a chance of opening it - a safer bet might be to use the lower resolution versions (still 2km and 8km pixels) - an excellent choice for wide 'locators' such as entire continents or countries.
You can check the resolution at this link (cloudless) and also here (including atmosphere/clouds).
Download the KML file to allow you to view this as a live layer of satellite imagery on Google Earth.
The 'Rapid response system' is used to view near-real time satellite imagery which is useful for navigating and downloading more localised and regional images, as well as images of natural phenomenon such as hurricanes and wildfires. You can search the Modis archives here.
Another site that is a little more technical but I have found useful is the Earth Science data interface (they are very helpful if you have particular requests)