Strategy, "modability," and the science fiction theme are all important game features for me. But the two things that keep me playing SEIV (as opposed to other 4x games) are the community and PBW. There is no community as helpful (and interesting) as this one, and PBW is the best multiplayer system I've seen. There's nothing like playing real real humans to make the game a challenge. Now, if I could only figure out how to defeat real humans...
