Hey Bob,
This question has been asked and discussed many times here at the ranch

You can use the search function to track down old discussions, but in the meantime I'll share with you one of my favorite reasons for getting certified:
When I was studying for my
SCJP I learned cool, useful stuff that I never would have learned otherwise. I don't know about you, but without that kind of external push, I tend to learn just enough to do stuff I need to do, and I probably miss out on better ways. I truly feel I'm a better programmer now than before I got my SCJP, and the Sun certifications have gotten more and more "real world" lately - they used to be kind of trivia tests.
- Bert