
A small explanation of the choices:
- Options 1 till 4 speaks for itself; The different Windows versions. If its 32/64Bit doesn't matter. You can write this down below if you want to.
- Mac OS: If you are using a Mac OS based system, and not forget to mention which one like Leopard for example.
- Linux OS: Again not forget which one because there are several different versions of them avaliable.
- Mixed: If you are using a Windows system and a Mac one, or Linux. So you are not only using strictly 1 OS but different ones also.
- None of them: A funny one and might sound silly, but lets wait and see

I voted for Windows 7 Ultimate (64Bit). Why? Its stable, runs very good, everything works as it should and im quite happy with it. I might upgrade to Windows 8.1 but im not enough convienced yet to take that step. I never used any Linux based OS in the past and not planning to use it either but im curious about it and might try it one day. My brother has a Macbook (don't know which one exactly) and only used it few times so I can't say much about it. Im not such a fan of any Apple products but thats my opinion which is personal.