proof that Vista is not a successful OS lies in the fact that not many business desktops have switched to it, but instead stayed with XP. Vista sales are going so bad that MS didnt even release the sales figures (# of vista copies sold) for the last quarter.
MS really needed a new OS to make even more money as the world was saturated with XP platform, so they came up with Vista. The problem was that Vista was not a completed system and wasn’t compatible with a lot of other applications, even though it was already delayed in its launch. I would probably say though, that I’ld expect Windows 7 to be much better than Vista and XP together…