In what context? Windows for gaming. Mac for production crap(music mainly). Linux for everything else.
Yes, It's quite personal. My PC is personal. It's mine. I make love to it every night. I think I need a girlfriend.
Really should be Windows, Mac or Linux. I guess enough people see Windows = PC. I think over the last 10 years, Windows have really done well in terms of production and post production products. I know I personally do a lot of things on Windows, that used to be considered Mac or bust. Like Photoshop or etc.