More likely is running Linux or BSD natively with Windows in a VM as needed (exactly what I do at work right now). They aren't even the best choice if that's what you care about (much of the FreeBSD core is nearly a decade out of date-it's that long since it was updated). But Macs and MacOS X are hardly the only option when it comes to developing in a Unix-like environment. I sincerely hope not! As a last resort, maybe.
