I still think that the most valuble cert available to this day is Cisco's CCNP. It is the second level Cisco Cert. The first level is CCNA (which is very valuable also) but more and more people are obtaining the Cisco base cert.
The Cisco CCNP cert will let the employer know that you have skills in networking and routing.
Even the CCNA cert is valuable - but not as valuable as the CCNP (I think that if you have this cert you HAVE to have some sort of knowledge of networking and routing- not just braindumps and transcenders to pass the test). But, there are always exceptions!
If you REALLY want to fly - get the CCIE. The top level Cisco cert. It is not easy - but once you get this cert you will be making no less than 6 figures. But, it requires a two day lab (at a cost of $1,000 plus travel expenses because it is only offered in 4 places in the world) and most people fail it the first time.
I am working on my CCNP. Maybe one day I will shoot for my CCIE - but I gotta take "baby steps!!"
Hope this helps!
Pinkman MCSE, CCA