While it's hard to advise people in a career direction when I am not sure of what their current security knowledgebase is, or what it is they would like to do, here are my thoughts.
If you are new to security, the Security+ certification is a good place to start. This is a very elementary exam with more of a technical approach. The CISSP certification would be the next step. It covers a wide range of topics, but has more of a managerial approach to security and how it relates to business needs. This is a good certification because it will broaden your ideas about what security entails and it is widely accepted.
The next step will depend on what you want to do with your career. Cisco and Microsoft include security certifications in their tracks, Plant3 has a series of quality wireless certifications and SANS has certifications that cover almost every sector of the security market.
Again, while it is hard to provide specific information because I do not know where you are in your career, I do know that these are the best certifications currently on the market.
This was first published in February 2006