Vista became usable after multiple service packs according to friends who used it, but by that time 7 was around the corner. Windows 7 was the last half-decent OS MS released. It only took two or three service packs, mostly security related. Vista took I think 6 service packs to become almost like W7 without its service packs.
Windows XP was far better than ME for a thousand reasons. Plus, back in the day. If you wanted to game almost at all you had to run Windows (Dual boot for me)
Windows is a game system. Not a operating system. I use *nix for everything if I am not gaming. It's a lot easier to game on *nix now but some games still suck or don't run at all no matter how much effort you put in. As such, I still dual boot.
XP was peak for it's time, and 7 was it's spiritual successor. Linux runs all of the games I care to play now. Windows is obsolete for my gaming purposes.