Lots of people saw this coming.
In 2005 I started telling my members to decrease their debt load, unload marginal properties while the prices were approaching the peak and improve their cash position. In 2006 I was talking about the coming recession when everyone else was chanting it would never happen. Through the first half of 2007 I was telling my membership to seriously consider selling most of their investments while the prices were still high.
Then at the start of 2008 I told them it was too late if they had not already taken action and discussions turned to scooping up bargains and effectively managing their holdings to weather the economic storm.
What I did not talk about was the hidden fraud at so many levels in the financial system. No one on the outside had any visibility to know that was happening.
I know it is human nature to look backwards, but that is not how you manage investments. The thing to do is take stock of where you are right now and adjust for what is coming. The US will be in a recession until the first or second quarter of 2010 AT THE EARLIEST. Depending on what governments do, it might drag out longer. The World will be in a recession until at least the beginning of 2011. Government will not solve this problem but they are going to make it much worse than it needed to be.
The economy that emerges will not be the same economy of the early 2000's. The hot and hyped investing strategies used before won't work post this recession. A return to fundamentals is the best course of action. Appreciation is nice but cash flow is required. Buy and hold investors will do well post recession if they are buying during the recession.
The era of real estate daytrading (flipping, wholesaling, etc.) is fast coming to a close.
Of course, all of the forward looking items are just my opinions and your actual mileage may vary.