After years in the Microsoft I am finally learning Java and Eclipse. For anyone familiar with C#, Java is extremely close but feels its age. No properties, delegates, or events? I can live without them. Eclipse however is another story. What AN AMAZING PIECE OF SOFTWARE! Miles ahead of Visual Studio in many areas. Mainly it just works; which is a huge kudo to any piece of complicated software.
And Eclipse is free. In fact, one person with a laptop, GMail, Eclipse, and SourceForge is the equivalent of a five person company from the 1980s.
Open-source software is unstoppable in many ways. You just can't compete with free. Software tool vendors have to keep moving into more and more niche areas. All the big ones, like source controls, IDEs, and bug tracking, are well covered by OSS. That being said, Microsoft has something like 50 billion dollars in the bank. They could not earn a cent for the next ten years and keep paying every employee. That's kind of unstoppable too!