It comes with Windows, but if you want a real operating system, you can install any Linux you like on there. Or a BSD. Go for it.
Also, I was going to just answer "mu" to your question, and be done with it. Macbooks don't have quality construction; that's why their hinges keep falling apart after a year or two of actual use. It's been a problem since the Powerbook days.
So, uh, yeah. Apple products are too fuckin' expensive.
(Oh, and there were a handful of VAIOs that also fit this criteria, but let's be honest, VAIOs are not real computers.)