Project Management: PMP certification or not?

Even though many engineering professionals hate to admit it there comes a time in life when one needs to think about being certified in project management. PMP certification or something like that seems to be the way to go, but the requirements are extensive and the tests are fairly expensive. Here is what I have got surfing the net:

http://corporategeek.info/what-you-will-not-earn-pmp-certification

http://pmtips.net/pmp-certification-worth-analysis/
http://pmtips.net/project-management-pmp-certification-worth/

http://techrepublic.com.com/5208-12848-0.html?forumID=102&threadID=277912&messageID=2632563

http://www.eng-tips.com/viewthread.cfm?qid=264620&page=1