This Q&A was doen a few days back...
PCA In your opinion, where does Linux shine versus Windows? Reliability? Virtualisation?
Torvalds: I think the real strength of Linux is not in any particular area, but in the flexibility.
For example, you mention virtualisation, and in some ways that's a really excellent example, because it's not only an example of something where Linux is a fairly strong player, but more tellingly, it's an example where there are actually many different approaches, and there is no one-size-fits-all "One True Virtualisation" model.
There are many different levels of virtualization, and many different trade-offs in efficiency, management, separation, running legacy applications and system software, etc.