I recently watched Secret of Kells, an animation released in 2009 that's been repeatedly recommended to me. The animation is breath taking, I keep having to re-watch sections of it. In distant 'shots', figures stand in uniform to make and appear like an ancient tapestry, or an illustration from the Book of Kells itself (I initially mistook the style as a product of Disney; that it was made by the same studio as Kim Possible!). The use of painted texture and level of detail is beautiful, even the snowflakes are celtic patterns.
Here are some of my favourite stills from the film.