How can I identify the most predictive factors? I've been playing around with bagged trees and random forests. How can I tell what factors most influenced the categorization? Will scikitlearn just spit it out, or is it trickier than that?
It basically lies within the fitted object. 

model.fit(X, y)
importances = model.feature_importances_


The importances are in the same order as the columns of features ($X$).