I've been around this industry for a while and in my experience, I've never run into any problems where not being certified has hurt me. I'm sure that it can help get your foot in the door, but it's never been necessary for me and I've been gainfully employed since '89 without any gaps between jobs.
Not to say I'm not interested, though. Over the years I've set out to get several certs only to get bored and give up. I guess I figure I have a job and it probably won't get me anymore money, so why waste the time. Also, it seems my responsibilities change too quickly and the old cert is no longer applicable to my job.
However, I am seriously contemplating SCJP certification now and think I'll actually try to get this one!
For me, it's more of a personal thing to know for myself that my knowledge is at a certain level.
I don't think too much of a college degree, either. In this industry, experience is 100% more important than any piece of paper. Especially when I know that colleges can't keep their curriculums up to speed with the technology changes. So when I'm hiring contractors, I don't scan for a bunch of letters after their name. I look for past experiences similar to my current needs. If they have that, I do the interview and test their knowledge then.
So, IMHO, do it for yourself, not for anyone else. Unless you know *for sure* you'll get more money from your employer. That's a nice incentive!