I tried OS 7, 8, and 9. While fun, it was useless for anything meaningful, except printshop. (Although Sad Macing the system was fun
)
I tried OS X a bunch of times, and I still don't like it, although I think it's better than any of the previous Apple OS's. The only thing I think its good for is surfing the web in a very safe fashion, since hardly anything can infect a Mac.
I liked DOS 5.0 and 6.2. 6.0, 6.21 and above were crap.
All the versions of Windows before 3.0 sucked. It wasnt evident how much 3.0 sucked, until 3.1 came out. Windows 3.11 was the ultimate DOS GUI
(Note: All windows before Windows 98 were not OSs, just nice GUIs for DOS [Whichever flavor you loved best]. Some would argue that Windows 95 was an OS not a DOS GUI, but I disagree since the Windows 95 GUI was basically just glued onto DOS 7.0)
Windows 95 was interesting, but so full of bugs you basically had to fumigate your system, and it loved to crash. This was finally fixed for the most part by Windows 98 SE, which was a great OS. Windows 2000, while not a mainstream consumer OS, was user friendly and rather stable, but not quite on the same level as XP. Windows ME was total crap.
XP is the best windows to date, very stable, and very user friendly.
Give me XP any day