From their 2008 Q4 earnings report ( http://investor.google.com/releases/2008Q4_google_earnings.h... ), Google-owned sites generated $3.81B while partner sites generated $1.69B.
I think the act of comparing the amount Google makes from AdWords to AdSense is moot -- Both of these channels are very successful. Both of these numbers end with a capital "B".
So question: Do I become an ad broker and take on Google or simply utilize Google to display ads on my property and make some coin?
At this point, I don't care how much Google is making off of me as a percentage, but I do care how much money I actually do put in my own pocket.