Yeah - and really it depends on your company. Big companies (GM, Cisco, etcetera) are ALWAYS more dangerous than small companies.
If Cisco or Nortel has a bad quarter they will just let 3000 people go on a whim. It happens often.
The problem with smaller companies is that they can go under - which is happening lately - happened to me last year.
however the company I am with currently is "immune" to the economy. We do insurance. Insurance is always necessary. We ride on the backs of hundreds (or thousands) of other companies - I don't know how many we serve really. Anyways, if one of them goes under, it doesn't matter because we get the business for whoever takes their place!