Favourite is a difficult choice. I use Windows 7, as I use a number of programs that don't have a linux alternative (or more specifically, the alternative is inferior). Steam is currently working on porting to Linux, and if that works out, Linux just might become my choice OS in the future, but in the meantime, Steam and most other games are Windows only. Yes, there's WINE, but performance is finicky and it's just too much hassle for me to bother with when Windows works fine for me. I do like how Linux OSes are generally faster than Windows, but to be honest, Windows does get a lot of bad hype because of its defaults. If you know what you're doing, you can speed Windows up greatly, not to mention there's a fair bit of room for customization that's "hidden" out of view. And let's not get started with Microsoft bundling IE with Windows. However, I've never found Windows to have the instability that some people claim. I've never seen a BSoD on my current rig.
From my experiences, Linux is great, but the available programs suffer in the gaming category. There's also serious issues with drivers, although that's improving (ever tried to install the driver to a WiFi dongle?). With all that being said, Windows 8 looks awful, it's obviously made for tablets, and I think Microsoft is out of their minds. I recently had the opportunity to try Macs at my university, but found they were by far the worst of the "big three" OSes. Safari crashed on me, Microsoft Office failed to open, and the whole OS sort of froze up on me at one time. Macs are also outrageously overpriced for the components that go into them. Windows has a fair price, in my opinion, if you buy the OEM version, but the pricing is crazy in stores (I saw Windows 7 Home Premium for $222 at Walmart).
Long story short, Linux has a lot of potential, but it's not for me. Windows 7 is the most balanced for me, but no way in hell will I update to Windows 8. And Macs? Macs are just garbage.
