Back when I was "important" (ie. before I got told how really unimportant I was when I was sacked), our business had a history of 8 year cycles -- peak to peak. We had followed these cycles +/- 1 year for 4 prior cycles. I got laid off in early 2002 and it was pretty close to the depths of despair. I would say that hit in 2003. That would put the next down cycle to be in 2011 but we should all feel the pain around 2009 - 2010.
Amazingly, this would just about coincide with the "next great depression" Harry Dent has been trumpeting to begin in 2010. Delving into his tea leaves is a subject for another thread.
On the plus side, we should have a strong up market between now and around the middle of 2009. Harry's latest forecast is Dow 16,000 which is a far cry below his original Dow 30,000 he was hyping in 2000. I wouldn't hold either of his predictions as the time to get out but we should have a good run. I see Dow 16,000 as a reasonable upside. A 25 to 30% bull run over a 12 to 16 month period is not a big deal from an historical perspective.