I think some borrowers have to take some of the blame as well, albeit with the tacit approval of the banks. Banks were lending 7x income mortgages interest only on 110%ltv, but people were still taking them out, even though they might not be able to pay them back if house prices dropped, or they lost an income or their circumstances changed for any reason (illness, babies, job loss etc).
Then people would remortgage houses which had "risen" in price and then spent the money on holidays, cars "loan consolidation", in my opinion not accepting that this was borrowed money, not actual money.
Having said that, I don't think apportioning blame is all that healthy, the problems are there and blaming the banks or individuals isn't going to fix it anyway.