I have never really worried whether I was certified or not. This Computerworld article gets right to the point:
Depending on whom you talk to, certification programs are either borderline rip-offs that provide little useful knowledge, or valuable hiring tools that make it easier for IT execs to pick the most promising new employees.
Available from vendors focusing on their own products, or outside organizations offering multi-vendor training, these certificate programs are expanding to fill the many specialized technology subsets that have multiplied along with the growth of data storage and other IT areas.
Now this isn't to say that I don't have a few IT certifications under the belt and didn't receive some benefit from them. One of the most intensive IT certifications of recent years was in IT security and another to "please" the crowd was a certification for migration to Microsoft's Server 2003. By the time I was done with those certifications though, I didn't know enough to get the job done.