The problem with any of the banks announcing losses right now is that it is conjecture. They are announcing losses on assets that they cannot price, cannot sell, and are merely guessing at what their value is as best they can. Each bank will be pricing differently, and every bank will be wrong. The credit markets are closed, and they are teetering on every bit of news that comes out. The US is pretty much likely on the way into a recession, and it would be a weird change of history if it doesn't drag others in with it. People experienced enough to know are marking this back to being comparable to 1990 rather than 1998. It is really bad right now.
At the same time you have petrochina as the biggest market cap firm in the world on the base of some very weird, protectionist small percentage IPO. You have oil at $97. You have commodities booming, You have SWFs looking to pour money into everything. You have hedge funds and (especially) Private Equity firms over capitalised. There are many things that could turn this around, but as delinquencies on loans begin to seep into credit cards and housing negative equity sets in, it isn't pretty.
For NR, they had no problem other than a market on which they depended closing up on them. The assets they have are good quality, but you can't sell anything in that market unless it is through a state guarantor (FanMae, FredMac - that's it) and that doesn't exist in the UK.
CDO's and CDOsq were something that was a symptomatic bad of the SWFs and seek for earning money in a non-volatile market. Many people were responsible, but it was dependent upon one thing. Housing prices went up. And for the first ever time, the whole US (bar NY) ha correlated to one on housing declines. A big house of cards.