Windows 7 is the best OS for me so far. It is way batter than Vista, I noticed a big difference in performance when I upgraded from Vista to Windows 7. I recommend for everyone to upgrade to Windows 7 if they have Vista, I can guarantee you will notice a big difference.
I run Windows 7 Ultimate 64-bit on my desktop and that's it pretty much. I would love to own a Mac since I've used the Mac OS X Operating System in Graphics and Technology and I enjoyed the aspects of it that Windows doesn't have. A dream setup for me would be my gaming desktop with Windows 7 and a Mac laptop with Mac OS X.
Windows Vista, it's decent and I've never had any problems with it but I really want to upgrade to Windows 7.
My laptop came with Windows 7 Home Premium, so that's what I use. I never used Vista, and skipped right from XP to 7. I love it. It's very clean and organized, and I love the taskbar with all my programs in it. I've had no problems with Windows 7, I look forward to Windows 8.