Well, I'll give an honest view based on my knowlegde about each of them.
Mac - Macs are easy to use, they are ideal for people who have little knowledge of computers. They are not that customisable, as in, little programming support from Apple. There's a big controvercy as to macs do or don't get viruses. In my opinion Macs are overpriced.
Windows - Windows can be a bit more complicated than macs. In my opinion I think Windows is safer than macs because antivirus companies catch new discovered viruses fast. Lots of development support from Microsoft's websites(FREE development software for personal use, now thats better than macs).
Linux - Can be hard to use, you have to install somethings through the terminal. It has a lot of customisation available. Although there are some antiviruses that exist for linux also (such as avast) but I'm not sure if you need them. Lots of open source alternatives available, even though you can run windows programs through something called Wine, but wine has been known to catch and run windows viruses on your linux machine.
Whats best for me is: Windows, because I have alot of programs that run on that. I like a bit of developing on the side and I think it is safe.