.NET will be the new COBOL, maybe not the most hip technology, but millions of business systems will still be running on it for years to come.
I’m a systems guy, so I’m accustomed to Active Directory, Exchange, and server OS. Knowing how reluctant companies can be to upgrade, I have no doubt that there will be plenty of work for me for a couple decades. I AM seeing a shift in server hardware toward consolidated platforms (i.e. Cisco blade systems), but the OS world will be hard to change for a while yet.
You're probably right -- though I got to say that at least COBOL seems to be a fairly stable system. [The last time there was a big COBOL mess it was the Y2K bug, and that was addressed.] Given that it's on the big mainframe as the back-end to a lot of transactions it'd have a lot of pressure to be stable whereas the desktop arena seems to have a surprisingly high tolerance for bad/broken software.