Considering we've already had one discussion of environmental effects of suns, I figured now would be a good time to discuss other ideas for the galaxy creator.
Personally, I think it might add a lot to the game if there were an option for players to start with two planets, with each of them in different systems. It would definitely make the game world seem bigger from the beginning, and in the "standard" 5 system ~20 planet current setup playing with ten AIs would really create the feel of a collapsing trader empire. Diplomacy would also become much more important.
My second idea might work better for games with only one or two large systems. What if the distance from the sun had an affect on what types of planets you found. For example, at the far ends of the system you would find ice planets, then Earth-like planets, then desert planets, and finally volcanic planets as you got very near the sun, with various asteroids dispersed throughout.