[Zammy-Sam]

Eliezer, I don't think such a thread will lead anywhere.
An operating system is a system you work on. The applications you need for your work or entertainment specify your choice on the os. If you are into gaming, then you might want to use windows as a platform. If you are into software developing you might rather pick unix. If you are into graphic design, macosx might be your choice. See, it's so much dependant on what you want to do with it. Most of the apps I use are better on macosx. Together with some hardware-related aspects this became the reason I chose mac.
Your questions is like: what's the best car? Can you say that?