I'm still running Windows XP Pro on both my desktop and laptop.
I bought a new desktop last fall with Windows 7, and found out some of my client's software isn't compatible with 7. I went back to my old one with XP Pro. Till I figure out what to do with it, the new one on Windows 7 is basically a $600 paperweight.
I went to a three day seminar earlier this week, and we were asked to bring our laptops, if we had one. I have a little 13" to carry around when I'm on the road. One fellow had a new laptop running on Window 8, and he was so lost in the woods he just gave up and looked at his neighbor's.
My wife's computer has Windows 7, and she gets along great with it. But--she isn't involved in all the business functions I am.
One thing I can say for sure, avoid Windows 8 like the plague.