Silly question IMO. There's no correct answer.
Windows is good at gaming, industrial tasks, office tasks and general usage.
MAC OS is good at multimedia and general usage.
Linux is good at industrial tasks, office tasks, gaming, multimedia, mobile applications but is not as good for general usage as some OS's are really complex to understand, and some don't even come with a user interface :p
Each perform moderately the same. MAC and Linux are more powerful in terms of programming (Linux = C/C++/C#, Windows = VB) and the way they're built, but then again the worlds most powerful scientific project ever was made using WINDOWS.
Appearance wise there's nothing between them. It's just what suits the user best. In my personal preference I prefer windows 7; it's easy to navigate around and keeps shit simple.