They are winning contracts left right and centre (One of more contract PR's being put out daily) so it certainly doesn't appear as if demand for their services has dropped off. The way to kick start an economy is through infrastructure and JEC is one of the most diversified infrastructure play out there.
I've heard the opposite! Jacobs has such diverse markets as well as geographically diverse customers that things are going very well despite this downturn in global spending. Jacobs is in Oil/Gas, Aerospace/Defense, Pharmabio, Heavy Construction Eng/Arch, etc., etc., etc. The abosolute best way to get the various economies going again is for countries to spend, spend, spend - infrastructure, defense, etc. You will be kicking yourself in '09 if you sell now. The time to buy is now!