Well, what I can say is that my CCNA brought me a job.
I took the CCNA exam (with 87% for 26 minutes from 90 given) at the beginning of March, 2003. 3 months later I was invited for a job in Cyprus and the managers there paid a lot of attention that I have Cisco certificate (which in my point of view is stupid).

However a certificate + knowledge will give you a lot.
The certificate is the thing that will allow you to open the door and enter the room. The knowledge behind that certificate will allow you then to stay into the room. That is my theory.

IMHO, a CCNA + RHCE (RedHat Certified Engineer) is a very good start and can open a lot of doors.