Race for the Galaxy
Amazing game. A gigantic tech tree where everything stacks with everything else. No leader bashing or direct conflict at all, not even the "I take Captain so that he can't" conflict in Puerto Rico, only parasitic leeching off of everyone else's actions. I played it yesterday over 10 times. Did I mention it's quick, too? Easily under an hour for 4 new players, and it looks like not-half-asleep 2 player games could be a mere 15-20 minutes.