Those Screenshot of Windows 7 you have been seeing are not really Windows 7. There will be a real "new" O/S feeling to the new offering from Microsoft. To support this I offer the following glimmer of understanding :-
"One of the main focus points of Microsoft in the creation of Windows Vista was to make it visually appealing. They spend lots of effort to add eye-candy to the operating system which made many users who wanted a visually pleasing operating system happy. Other users however disliked the eye candy because they associated huge resource usage with it. The step from Windows XP to Windows Vista was a visual one. Everyone who worked with both operating systems for some time could tell the difference between the two.
The available Windows 7 screenshots and Windows 7 videos on the other hand look a lot like Windows Vista; So alike that many users would probably fail to distinguish between Windows 7 and Windows Vista at this point. This could mean two things. Microsoft might be tempted to optimize the eye candy and reduce the hardware requirements instead of adding even more that would put a lot of potential buyers off again because of the increased hardware requirements. The other scenario would be that the eye candy will be added at the end of the development phase or that it simply has not been added yet but is more or less ready to be included.
The Windows 7 release that is coming out these days will hopefully shed some light on the issue. The good news is that Windows 7 themes will not be that different from Windows Vista themes which essentially means that it will still be possible to patch the relevant system files to add custom themes to the operating system." http://windows7news.com/2008/10/26/windows-7-theme/