I highly recommend this video of a talk given recently by Sony Kapoor at the Global Systems Dynamics Workshop in Berlin. As it happens, I was there and got to see the talk in person; it's funny and very insightful. Kapoor used to work at Lehman Bros (well before it's collapse), and eventually quit investment banking to do more useful things -- he now works at Re-define, a think tank on public policy.
I tried to embed the video here but failed. There seems to be embed protection on it for some reason.
There were a number of other great talks at the meeting as well, all available on video here.