I have Windows 7 in the newest computer.The older one use Vista.The old computer has Windows XP.The oldest computer has Windows 98. I use Firefox in place of windows garbage.
Windows 7 here, as well. I have a computer with Windows 8 on it as well... and, while I like it... I'm not sure how practical it will be for professional use.
I run Linux Mint 12 Cinnamon on three machines and Linux Mint Debian Edition on a fourth. Two of the Mint 12 machines are dual boot machines, with Win 7 on them, as well. I've not seen a Windows desktop in 3 or 4 weeks, however.
My favorite operating system was windows xp because, it was easy to use and very user friendly. But on laptop i have windows 7 and i found it much better than windows xp.
I now have a MacBook Pro. Using it now, actually. That said, I still can't imagine using it for work on a permanent basis. It's great for general purpose, like now, and I'll likely use it when I'm working remotely, but my desktop will likely remain as my primary workstation when I'm home.
Windows 7 is my favourite but any windows system is cool for me. I'm a fan of Vista and even XP. I'm too stuck in my ways to try any apple operating systems or linux etc so these do fine for me Just Habbit as I was brought up with Windows