Certified Information Systems Security Professional (CISSP)
Check out www.isc2.org (the developers of this certification).
There is no comparison between CISSP and vendor specific certifications. Vendor certifications certifiy you on a specific set of hardware or software.
CISSP is vendor-independant and is based on best practices / international security standards.
Value / prospects: First, this is not an entry-level certification. Minimum requirements include 3 or more years dedicated experience in one or more of the IS security domains covered by the certification.
This certification would obviously get you farther with a large organization (like a Boeing or an Intel) or IS Security firm than it would with most small businesses. If an organization doesn't have a dedicated IS security department or division, chances are this certification will mean nothing to them.
Obviously Information Systems Security is getting more and more exposure as the nature of elctronic and internationl commerce changes. If you have the experience to back it up, this certification could be an added bonus when trying to get a security-specific job.