Wow, didn't realize there was so many programmers on this site.
My suggestions are generally that the big three languages are C++, Java and C#. The general trend seems to be that the C++ jobs are becoming higher paying because the pool of talented C++ developers isn't growing and students are coming out of college not knowing C++. C++ has the longest learning curve and you'll find that your average coworker won't have invested the time to fully master the language, while there's a higher chance of coworkers mastering the other two languages I will mention.
According to some sites, Java is in the lead, but it seems like the margin is dwindling. Java's niche seems to be middleware and has a strong foothold in the embedded world, due to the portability aspect. I've had multiple recruiters tell me that C# is growing fast as one of the most heavily used languages in the industry. Knowing one of the three is extremely important. If you're starting from scratch, I'd probably say to go for C#. My main knock against C# over Java in the past has been the portability aspect, but now with how far Mono has come, that's becoming less and less of an issue.
As for certification, it's worthelss if you're a software developer. Degrees are worth a lot (BS, MS, MBA, in particular), but certifications won't get you a dime extra.
P.S.: The one area where I wouldn't suggest C# or Java over C++ is game development; most game development companies are heavily invested in C++ and will be for a long time.
[Edited by - Solace on Aug 01 2008 2:28 PM]
Wishing everyone well. I enjoyed posting here for a while, but as I matured I realized this forum isn't for me. We all evolve. Thanks for the memories everyone.