My Enviroment Background doesn't show up? I'm trying to do a Space scene on Cycles so i'm using a Star map background as an Enviroment Map, i made the Nodes already, the texture/image shows up on the Preview..but not in the Render, why? It's the last step i need for this render but this is still giving me troubles :/
The environment is not showing up in the render because you have Transparent checked in the Film section of the Render property panel. Uncheck that and it will work.

I would also add that if you DO want to composite the foreground and background element, to leave the Transparent box checked. Then you can enable the Environment render pass and combine the foreground and background renders in the compositor.