I'd have to say the Jedi, only because they had the potential to have an Order being truly Grey, but instead changed it (I'm not sure why) from this:
Emotion, yet peace.
Ignorance, yet knowledge.
Passion, yet serenity.
Chaos, yet harmony.
Death, yet the Force.
To this series of absolutes, which directly flies in the face of reality:
There is no emotion, there is peace.
There is no ignorance, there is knowledge.
There is no passion, there is serenity.
There is no chaos, there is harmony.
There is no death, there is the Force.
The old Jedi were the real badasses; able to acknowledge their limitations as living beings yet strive for making themselves better.