None! I have sysadmined Solaris and Linux datacenters, found errors in a vendor's documentation of their 2780/3780 protocol, installed an entire test environment with 8 Solaris boxes and 24 PCs over a weekend, taught Sybase's Advanced System Administration course, served as project leader, technical mentor, and a department head in in-house software development and maintenance.
So far, thank the good Lord, I have found employers that take the time to look at what I can do rather than lazily examine cert lists. BTW, my college degree is a Bachelor of Arts, not BS.
OK, now that I have that out of my system. Certs are extremely useful as a way to familiarize yourself with a new environment, or more deeply with a known environment. And if there is ever any kind of standardization, I can see them being useful for screening hires - after all, I did get a college degress in Computer Science to catch the eye of future employers. However, I have found an irritatingly small correlation between certs and abilities in the real world. My dear mother was very good at studying and tests, and was the only student in her college calculus class to get an A. The teacher was speechless (literally - he couldn't think of what to say and offered her a cookie instead), as my mother clearly didn't understand calculus, something she freely admitted when she told this story.