If you want to know how the next version of windows is going to look like, then you can look at this site where snapshots of the next generation windows (named Windows 7) have been posted.
I did not find any big deviation from Windows Vista except for changes in the look'n'feel of applications like calculator, wordpad and paint. All of these have their menus looking like that of Office 2007.
I am sure there must be a lot cooking than improvements to these utility applications.
Below is a video of how the calculator looks in this engineering build of Windows 7.