My salary proves that an MCSE certification is not completely useless. It got me the jobs I've had the past few years.
As far as why we bother with Microsoft certification: the rest of the world, however enlightened or unenlightened they are, use it. It may be buggier than Linux... it may be less secure than Linux... it may be slower than Linux... but just about EVERYTHING is made for Microsoft Windows. Doesn't matter if I agree with you or not. The world needs people to fix and support Microsoft-based solutions... especially if it doesn't work!

See what I'm saying?
We're all tech whores. We learn what the market wants us to learn because the market decides to use the software they want... not what you want them to have. And I'll be honest: even with my Linux experience/certification, I don't go searching for a pure-Linux job. I can't. There's just not enough of them out there.
Additionally, why even start a Microsoft w/IIS vs. Linux w/Apache debate when we're talking about general network administration? Most techie jobs have nothing to do with Web server administration. In fact, I try my best to stay away from the Web server side of the house.
Anyway, to the real matter at hand: congrats, Teknoid... even if I'm late in congratulating you. I've got quite a bit of certification experience to go with my real-world battles. If I can be of any assistance to you regarding future certifications, feel free to e-mail or PM me. Suggestion: Stay away from the Network Design test. It's poorly written, and from what I've seen, sometimes the correct answer just doesn't exist - those with real world experience are just as likely to pull their hair out than answer correctly. It's luck-of-the-draw whether you pass or not. I'd highly suggest Security Design (70-220?) for your 'mandatory' elective.
Hope this helps!