I tend to look at certifications as a very good foot in the door. Honestly, I can't see a company hiring a guy with 15 years experience and no certs over a CCIE or MCSE with 10 years. Experience is definitely a key factor in job placement, though certifications will most likely put anyone ahead of the game. I mean, if certifications are useless... what are there so many vendor specific certs?
If I'm a CIO and my network is run completely off Cisco equipment, then you better believe I'm going to hire the CCIE with 10 years experience most likely using Cisco equipment over the guy with 15 years experience doing who knows what.
If certifications didn't mean anything, college courses wouldn't be geared towards attaining them, major vendors wouldn't worry about getting people certified in their product, and the average salary of a MISM would be higher than a CCIE.