Read a posting by Donald Smith about continuous Eclipse demand. He used Indeed.com job trends as indicator.
Curious as I am I started to play with it:
Looks like .NET is more required than J2EE. But if they are right it is better to know about C than Java, C++, C# or Assembler.
Or maybe it is better to learn E since it is more required than C or Java. Yes there is an E programming language. But maybe it just counts the character or counts e's like in e-business.
There is also an interesting race between Rails and Seaside.
In the end we should also not forget to compare apples with oranges... ;)