Hrmph. I chose rock/none and advanced storage for very good roleplaying reasons; my race were a race of self-replicating industrial robots that had originally created to do space exploration and development for an organic species. I was rock/none+adv. storage _before_ it was cool!
I think that ultimately the best atmosphere/planet type to choose for your race is "the one that nobody else is using in that particular game." Good luck guessing.