Well, you could combine the novelty with affecting certain areas of the game that will have a more limited impact on the game. Areas such as production times, cost of Structures (ie, a planet that is as flat as a board reduces the cost of building a structure - plus think of the novelty of having a Flat Planet
), etc. Typically, i dont think that a planet should give you more resources as (like Gate said) that would prolly be the most obvious option to take, as resources is life!
heh