With the interest rate as low as it was, all banks should have been DEMANDING traditional loans, not fueling the fire with low interest rates AND psycho loans. I hold the banks and any other institutions that allowed these loans 100% responsible for the bubble.
Many on here, I believe, would hold the consumer responsible. While there will be some tough-love education coming up, most people do not educate themselves before they get a loan; they trust the bank. This puts the bank in a position of responsibility for ensuring the consumer can pay for the loan.