Aura Matte - absolutely gorgeous in navy blue. Will definitely hold up in a kids' room. The gloss level in paint isn't enough to act as a reflector of any significant quantity of light. Plus there's scatter issues. The idea that shiny paints somehow reflect a useable quantity of light back into the room is more myth than fact.

I agree with fun ^

The only thing shiny dark blue paint will do is make every flaw in the sheetrock show up.

When you say "dark" .. think "cozy" and add more lights.

I did my bathroom in dark blue and used eggshell finish, which was perfect, as it deepens of the color and doesn't get rub marks as flat would.