I'm surprised you didn't list Apple or Walmart. Also, I see the USG as becoming less "rational" (perhaps this is inevitable as a nation-state becomes more democratic) and the Chinese Politburo becoming more so.
Note: I am employed by the USG.
Walmart - I agree, is a big miss. This thought was jotted down at my night time.
Apple, I genuinely don't think that they are genuinely restricting the future in significant ways. They have good products, but the majority of the future's consumers are coming from value-for-money areas like China, India and Africa (even in the middle-east, apart from the sheikhs, I don't see the average person having too much money). Apple's strategy is not going to fly there.
Most long term users on Less Wrong understand the concept of optimization power and how a system can be called intelligent if it can restrict the future in significant ways. Now I believe that in this world, only institutions are close to superintelligence in any significant way.
I believe it is important for us to have atleast some outside idea of which institutions/systems are powerful in today's world so that we can atleast see some outlines of how the increasing optimization power will end up affecting normal people.
So, my question is - what are the present institutions or systems that you would classify as having the maximum optimization power. Please present your thought behind it if you feel you are mentioning some unknown institution. I am presenting my guesses after the break.
Blogospheroid's guess list
Institutions I found significant outside this list is the Singaporean and Abu Dhabi city governments, very rational and increasing their significance in the world, but highly restricted from fooming because of constraints.